Organic light-emitting panel, manufacturing method thereof, and organic display device

ABSTRACT

A pixel in the panel includes sub-pixels  100   a   , 100   b , and  100   c . Bank  105   a  separates organic light-emitting layer of sub-pixel  100   a  and organic light-emitting layer of a sub-pixel of a pixel that is adjacent to sub-pixel  100   a . Bank  105   d  separates organic light-emitting layer of sub-pixel  100   c  and organic light-emitting layer of a sub-pixel of a pixel that is adjacent to sub-pixel  100   c . Bank  105   b  separates organic light-emitting layer of sub-pixel  100   a  and organic light-emitting layer of sub-pixel  100   b . Bank  105   c  separates organic light-emitting layer of sub-pixel  100   b  and organic light-emitting layer of sub-pixel  100   c . Inclination angle θcb of sidewall  105   cb  of bank  105   c  located on the side of sub-pixel  100   c  is set to be larger than other inclination angles θaa, θba, θbb, θcc and θdc.

This is a continuation application of PCT Application No.PCT/JP2010/006143 filed on Oct. 15, 2010, designating the United Statesof America, the disclosure of which, including the specification,drawings and claims, is incorporated herein by reference in itsentirety.

TECHNICAL FIELD

The present invention relates an organic light-emitting panel, amanufacturing method thereof, and an organic display device.

BACKGROUND ART

In recent years, progress has been made in the research and developmentof display devices that use the phenomenon of electroluminescenceoccurring in organic material. Each light-emitting cell of such adisplay device is composed of an anode and a cathode with an organiclight-emitting layer therebetween. When the display device is driven,holes are injected through the anode, electrons are injected through thecathode, and the holes and electrons recombine within the organiclight-emitting layer, thereby emitting the light.

Banks composed of insulating material partition the organiclight-emitting layer into light-emitting cells. The organiclight-emitting layer is formed by dripping ink, which includes anorganic light-emitting material, into each region separated by the banksand drying the ink.

Meanwhile, a problem with the organic light-emitting layer formed inthis way is that it is difficult for the layer to have a uniform filmthickness.

As one example of technologies for evening out the film thickness of theorganic light-emitting layer, Patent Literature 1 discloses providing aconvexity on the inner sidewall of the bank in order to control thepinning location of the ink. In other words, according to the technologyof Patent Literature 1, the pinning location of the ink dripped in onelight-emitting cell can be set to the convexity. With this technology,it is possible to secure a uniform film thickness to a certain degree.

CITATION LIST Patent Literature

-   Patent Literature 1: Japanese Patent Application Publication No.    2007-311235

SUMMARY OF INVENTION Technical Problem

It is considered difficult, however, to use the technology of PatentLiterature 1 to detect in advance how the organic light-emitting layerof a display device is uneven in film thickness and, based on thedetection results, form a minute convexity for each region or each innersidewall of the bank to a high degree of precision. Therefore, it is noteasy to maintain the organic light-emitting layer at a uniform filmthickness over the entire region of the organic light-emitting panel.

It is an object of the present invention to solve the above problems byproviding a display device, and a manufacturing method thereof, that hasa uniform film thickness in the organic light-emitting layer across theentire panel and has an even luminance within the panel.

Solution to Problem

In order to solve the above problems, an organic light-emitting panelaccording to an aspect of the present invention has the followingstructure.

The organic light-emitting panel according to an aspect of the presentinvention comprises: an array of a plurality of pixels; a plurality oflight-emitting cells which, provided in each pixel and arranged in analignment, emit light of different colors, each light-emitting cellincluding an underlying layer, a first electrode provided in theunderlying layer, an organic light-emitting layer, and a secondelectrode formed on an opposite side of the organic light-emitting layerfrom the underlying layer; and a plurality of banks which, formed abovethe underlying layer, define each light-emitting cell by separating thelight-emitting cells one from another, the plurality of pixels includinga pixel that is structured such that two inner sidewalls, which faceeach other in two adjacent banks defining a predetermined light-emittingcell among the plurality of light-emitting cells, have differentinclination angles.

Advantageous Effects of Invention

The above organic light-emitting panel according to an aspect of thepresent invention is structured such that two inner sidewalls, whichface each other in two adjacent banks defining the predeterminedlight-emitting cell, have different inclination angles. This structuremakes it possible to adjust the pinning location when ink is drippedduring the manufacturing. To be more specific, the larger theinclination angle of a sidewall of a bank is, the higher the pinninglocation is; and the smaller the inclination angle of a sidewall of abank is, the lower the pinning location is.

Also, after the ink is dried, the film thickness of the organiclight-emitting layer and the inclination angle of the bank sidewall havea reverse relationship. More specifically, the larger the inclinationangle of a sidewall of a bank is, the smaller the film thickness of theorganic light-emitting layer near the sidewall is, relatively; and thesmaller the inclination angle of a sidewall of a bank is, the larger thefilm thickness of the organic light-emitting layer near the sidewall is,relatively.

Thus, with the structure where two inner sidewalls, which face eachother in two adjacent banks defining the predetermined light-emittingcell, have different inclination angles, the organic light-emittingpanel according to an aspect of the present invention can prevent theorganic light-emitting layer in each light-emitting cell from becominguneven in film thickness and provide excellent light-emittingcharacteristics.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram showing the configuration of an organicdisplay device 1 according to the Embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing a sub-pixel 100included in a display panel 10.

FIG. 3 is a schematic plan view showing a bank 105 in the display panel10.

FIG. 4 is a schematic cross-sectional view showing the structure ofsub-pixels 100 a to 100 c included in the display panel 10 and banks 105a to 105 d that separate the sub-pixels 100 a to 100 c from each other.

FIG. 5A is a schematic cross-sectional view showing pinning locationswhen the taper angle of the bank sidewall is small; FIG. 5B is aschematic cross-sectional view showing pinning locations when the taperangle of the bank sidewall is large; FIG. 5C is a schematiccross-sectional view showing the condition of the organic light-emittinglayer after drying when the taper angle of the bank sidewall is small;and FIG. 5D is a schematic cross-sectional view showing the condition ofthe organic light-emitting layer after drying when the taper angle ofthe bank sidewall is large.

FIG. 6 summarizes the relationship between the inclination angle of thebank sidewall (taper angle) 0, the pinning height H, and the filmthickness T of the organic light-emitting layer.

FIG. 7 shows a distribution of film thickness of the organiclight-emitting layer in samples 1-3.

FIG. 8 shows a distribution of film thickness of the organiclight-emitting layer in samples 4 and 5.

FIGS. 9A-9C are schematic cross-sectional views showing, in order, themain processes in the manufacturing method of the display panel 10.

FIGS. 10A-10C are schematic cross-sectional views showing, in order, themain processes in the manufacturing method of the display panel 10.

FIGS. 11A and 11B are schematic cross-sectional views showing, in order,the main processes in the manufacturing method of the display panel 10.

FIG. 12A is a schematic flowchart showing a procedure of applying anddrying the inks 1060 a-1060 c; and FIG. 12B is a schematic flowchartshowing another procedure of applying and drying the inks 1060 a-1060 c.

FIG. 13 is a schematic cross-sectional view showing the main processesin the manufacturing method of Modification 1.

FIGS. 14A and 14B are schematic cross-sectional views showing the mainprocesses in the manufacturing method of Modification 2.

FIGS. 15A and 15B are schematic cross-sectional views showing the mainprocesses in the manufacturing method of Modification 2.

FIG. 16A shows the relationship between the taper angle of a bank andexposure/developing; and FIG. 16B shows AFM graphs that indicate theshapes of formed banks.

FIG. 17 is a schematic cross-sectional view showing the structure ofsub-pixels 300 a-300 c, non-light-emitting cells 300 d and 300 e, andbanks 305 a-305 e included in the display panel provided in the organiclight-emitting device of Embodiment 2.

FIGS. 18A-18C are schematic cross-sectional views showing, in order, theprocesses for applying the inks 3060A-3060C.

FIG. 19 is a schematic cross-sectional view showing the structure ofsub-pixels 400 a-400 c, non-light-emitting cells 400 d and 400 e, andbanks 405 a-405 f included in the display panel provided in the organiclight-emitting device of Embodiment 3.

FIG. 20 is a schematic cross-sectional view showing the state where theinks 4060 a-4060 c are applied at the same time.

FIGS. 21A and 21B are schematic cross-sectional views provided forexplanation of definition of the taper angle.

FIG. 22 is a schematic plan view showing regions 10 a 1, 10 a 2 and 10 bin the display panel 10.

FIG. 23 is an external perspective view showing an example of theappearance of a set that includes the organic display device 1.

FIG. 24 is a schematic plan view showing a bank 805 in a display panel80 of Modification 3.

FIGS. 25A and 25B are schematic cross-sectional views showing how thefilm thickness distribution of the organic light-emitting layer isuneven in a series of sub-pixels of the display panel.

FIGS. 26A-26C are schematic cross-sectional views showing the vaporconcentration distribution during formation of the organiclight-emitting layer, and unevenness of film shape in the ink dryingprocess.

DESCRIPTION OF EMBODIMENTS [Outline of Aspects of Present Invention]

The organic light-emitting panel according to an aspect of the presentinvention comprises: an array of a plurality of pixels; a plurality oflight-emitting cells which, provided in each pixel and arranged in analignment, emit light of different colors, each light-emitting cellincluding an underlying layer, a first electrode provided in theunderlying layer, an organic light-emitting layer, and a secondelectrode formed on an opposite side of the organic light-emitting layerfrom the underlying layer; and a plurality of banks which, formed abovethe underlying layer, define each light-emitting cell by separating thelight-emitting cells one from another, the plurality of pixels includinga pixel that is structured such that two inner sidewalls, which faceeach other in two adjacent banks defining a predetermined light-emittingcell among the plurality of light-emitting cells, have differentinclination angles.

The organic light-emitting panel according to an aspect of the presentinvention is structured such that two inner sidewalls, which face eachother in two adjacent banks defining the predetermined light-emittingcell, have different inclination angles. This structure makes itpossible to adjust the pinning location when ink is dripped during themanufacturing. To be more specific, the larger the inclination angle ofa sidewall of a bank is, the higher the pinning location is; and thesmaller the inclination angle of a sidewall of a bank is, the lower thepinning location is.

Also, after the ink is dried, the film thickness of the organiclight-emitting layer and the inclination angle of the bank sidewall havea reverse relationship. More specifically, the larger the inclinationangle of a sidewall of a bank is, the smaller the film thickness of theorganic light-emitting layer near the sidewall is, relatively; and thesmaller the inclination angle of a sidewall of a bank is, the larger thefilm thickness of the organic light-emitting layer near the sidewall is,relatively.

Thus, with the structure where two inner sidewalls, which face eachother in two adjacent banks defining the predetermined light-emittingcell, have different inclination angles, the organic light-emittingpanel according to an aspect of the present invention can prevent theorganic light-emitting layer in each light-emitting cell from becominguneven in film thickness and provide excellent light-emittingcharacteristics.

Note that, in the above description, the “inclination angle” is an angleformed by a side wall of a bank and an upper surface of an underlyinglayer on which the bank is provided (the underlying layer corresponds tothe first electrode, hole injection layer, hole transporting layer, orhole injection transporting layer).

In the above-described organic light-emitting panel, in each of one ormore light-emitting cells other than the predetermined light-emittingcell in the pixel that is structured such that the two inner sidewallsfacing each other in the two adjacent banks defining the predeterminedlight-emitting cell have different inclination angles, two innersidewalls facing each other may have equal inclination angles.

As described above, with the structure where two inner sidewalls, whichface each other in two adjacent banks defining the predeterminedlight-emitting cell, have different inclination angles, the organiclight-emitting panel according to an aspect of the present invention canprevent the organic light-emitting layer in each light-emitting cellfrom becoming uneven in film thickness and provide excellentlight-emitting characteristics. In addition, with the above-describedstructure where, in each of one or more light-emitting cells other thanthe predetermined light-emitting cell in the pixel, two inner sidewallsfacing each other have equal inclination angles, it is possible toprevent the organic light-emitting layer from becoming uneven in filmthickness and provide excellent light-emitting characteristics. Thismakes it possible to obtain excellent light-emitting characteristics ina plurality of pixels.

Note that the term “equal” above does not mean exact mathematicalequivalence, but rather takes factors such as dimensional error duringmanufacturing of the display device into account. Specifically, the term“equal” refers to making the inclination angles equal within the rangepermitted in practice by the difference in luminous efficiency (unevenluminance) between the light-emitting cells in the central region andperipheral region of the panel.

In the above-described organic light-emitting panel, the plurality oflight-emitting cells in each pixel may include a first light-emittingcell located at an end of the alignment, a second light-emitting celllocated at a central portion of the alignment, and a thirdlight-emitting cell located at another end of the alignment, theplurality of pixels are arranged to be continuously adjacent to eachother, and the plurality of pixels include a pixel that is structuredsuch that two inner sidewalls, which face each other in two adjacentbanks defining the first light-emitting cell, have equal inclinationangles, two inner sidewalls, which face each other in two adjacent banksdefining the second light-emitting cell, have different inclinationangles, and two inner sidewalls, which face each other in two adjacentbanks defining the third light-emitting cell, have equal inclinationangles.

With the above-described structure, when a non-light-emitting cell (forexample, a bus bar) is not provided between each pair of adjacent pixelsand ink is applied to form organic light-emitting layers in an order ofthe alignment, if the above-described relationships between the innersidewalls of the banks and the inclination angles are satisfied, thepresent invention produces an advantageous effect that it is possible toprevent the organic light-emitting layer in each light-emitting cellfrom becoming uneven in film thickness and provide excellentlight-emitting characteristics.

In the above-described organic light-emitting panel, the plurality oflight-emitting cells in each pixel may include a first light-emittingcell located at an end of the alignment, a second light-emitting celllocated at a central portion of the alignment, and a thirdlight-emitting cell located at another end of the alignment, anon-light-emitting cell is provided between each pair of adjacentpixels, a bank is provided between each pair of a pixel and anon-light-emitting cell that are adjacent to each other, the bankseparating the pixel from the non-light-emitting cell, and the pluralityof pixels include a pixel that is structured such that two innersidewalls, which face each other in two adjacent banks defining thefirst light-emitting cell, have equal inclination angles, two innersidewalls, which face each other in two adjacent banks defining thesecond light-emitting cell, have different inclination angles, and twoinner sidewalls, which face each other in two adjacent banks definingthe third light-emitting cell, have different inclination angles.

With the above-described structure, when a non-light-emitting cell (forexample, a bus bar) is provided between each pair of adjacent pixels andink is applied to form organic light-emitting layers in an order of thealignment, if the above-described relationships between the innersidewalls of the banks and the inclination angles are satisfied, thepresent invention produces an advantageous effect that it is possible toprevent the organic light-emitting layer in each light-emitting cellfrom becoming uneven in film thickness and provide excellentlight-emitting characteristics.

In the above-described organic light-emitting panel, the plurality oflight-emitting cells in each pixel may include a first light-emittingcell located at an end of the alignment, a second light-emitting celllocated at a central portion of the alignment, and a thirdlight-emitting cell located at another end of the alignment, anon-light-emitting cell is provided between each pair of adjacentpixels, a bank is provided between each pair of a pixel and anon-light-emitting cell that are adjacent to each other, the bankseparating the pixel from the non-light-emitting cell, and

the plurality of pixels include a pixel that is structured such that twoinner sidewalls, which face each other in two adjacent banks definingthe first light-emitting cell, have different inclination angles, twoinner sidewalls, which face each other in two adjacent banks definingthe second light-emitting cell, have equal inclination angles, and twoinner sidewalls, which face each other in two adjacent banks definingthe third light-emitting cell, have different inclination angles.

With the above-described structure, when a non-light-emitting cell (forexample, a bus bar) is provided between each pair of adjacent pixels andink is applied to form organic light-emitting layers at the same time,not in an order of the alignment, if the above-described relationshipsbetween the inner sidewalls of the banks and the inclination angles aresatisfied, the present invention produces an advantageous effect that itis possible to prevent the organic light-emitting layer in eachlight-emitting cell from becoming uneven in film thickness and provideexcellent light-emitting characteristics.

In the above-described organic light-emitting panel, eachnon-light-emitting cell may include none of the organic light-emittinglayers and may include the second electrode and a third electrode thatis made of a same material as the first electrodes, the third electrodeand the second electrode being electrically connected with each other.

In an organic light-emitting panel, the second electrode, which isprovided at a location upper (closer to the light extraction side) thanthe organic light-emitting layer, is normally made of alight-transmissive material (such as ITO or IZO). However, thesematerials have high electric resistance. These matters taken intoaccount, the second electrode and the third electrode are connected inthe non-light-emitting cell to reduce the electric resistance so thathigh light-transmissivity can be maintained to prevent a voltage dropfrom occurring even in a panel of a large size. The third electrode is,for example, a bus bar.

In the above-described organic light-emitting panel, two regionsadjacent to the predetermined light-emitting cell may have different inkvapor concentrations when ink is applied to the predeterminedlight-emitting cell, and among two inner sidewalls facing each other intwo adjacent banks defining the predetermined light-emitting cell, asidewall of a bank, which is located on a side of a region having alower ink vapor concentration among the two regions, may have a largerinclination angle than a sidewall of a bank, which is located on a sideof a region having a higher ink vapor concentration among the tworegions.

In the organic light-emitting panel, when ink is applied to alight-emitting cell that is adjacent to two regions having different inkvapor concentrations, the applied ink forming a light-emitting layer hasan inherent tendency to be larger in film thickness at an end located ona side of a region having a lower ink vapor concentration than at an endlocated on a side of a region having a higher ink vapor concentration.Due to this tendency, the light-emitting layer is likely to have anuneven film thickness.

However, with the above-described structure where, a sidewall of a bank,which is located on a side of a region having a lower ink vaporconcentration among the two regions, has a larger inclination angle thana sidewall of a bank, which is located on a side of a region having ahigher ink vapor concentration among the two regions, the pinninglocation of the ink in the sidewall of the bank located on the side ofthe region having a lower ink vapor concentration becomes relativelyhigher than the pinning location of the ink in the sidewall of the banklocated on the side of the region having a higher ink vaporconcentration. As a result, it is possible to restrict the filmthickness of the organic light-emitting layer in the sidewall of thebank on the side of the region having a lower ink vapor concentration,thereby preventing the uneven film thickness from occurring between twoends of the predetermined light-emitting cell.

Thus, with the above-described structure, it is possible to prevent theorganic light-emitting layer in the predetermined light-emitting cellfrom becoming uneven in film thickness and provide excellentlight-emitting characteristics in each pixel.

In the above-described organic light-emitting panel, a type of inkcorresponding to the predetermined light-emitting cell may be applied tothe predetermined light-emitting cell in a state where a type of inkcorresponding to one light-emitting cell among two light-emitting cellsthat are adjacent to the predetermined light-emitting cell in a samepixel, has been applied to the one light-emitting cell and beforeanother type of ink corresponding to the other light-emitting cell amongthe two light-emitting cells starts to be applied to the otherlight-emitting cell, and a sidewall of a bank located on a side of theother light-emitting cell may have a larger inclination angle than asidewall of a bank located on a side of the one light-emitting cell.

In the organic light-emitting panel, when ink is applied to apredetermined light-emitting cell in the state where a type of inkcorresponding to one light-emitting cell among two light-emitting cellsthat are adjacent to the predetermined light-emitting cell in a samepixel, has been applied to the one light-emitting cell and beforeanother type of ink corresponding to the other light-emitting cell amongthe two light-emitting cells starts to be applied to the otherlight-emitting cell, the ink vapor concentration is higher on the sideof the one light-emitting cell than on the side of the otherlight-emitting cell. Accordingly, the applied ink forming alight-emitting layer tends to be larger in film thickness at an endlocated on a side of the other light-emitting cell than at an endlocated on a side of the one light-emitting cell. Due to this tendency,the light-emitting layer is likely to have an uneven film thickness.

However, with the above-described structure where a sidewall of a banklocated on a side of the other light-emitting cell has a largerinclination angle than a sidewall of a bank located on a side of the onelight-emitting cell, the pinning location of the ink in the sidewall ofthe bank located on the side of the other light-emitting cell becomesrelatively higher than the pinning location of the ink in the sidewallof the bank located on the side of the one light-emitting cell. As aresult, it is possible to restrict the film thickness of the organiclight-emitting layer in the sidewall of the bank located on the side ofthe other light-emitting cell, thereby preventing the uneven filmthickness from occurring between two ends of the predeterminedlight-emitting cell.

Thus, with the above-described structure, it is possible to prevent theorganic light-emitting layer in the predetermined light-emitting cellfrom becoming uneven in film thickness and provide excellentlight-emitting characteristics in each pixel.

In the above-described organic light-emitting panel, two regionsadjacent to the predetermined light-emitting cell may have different inkvapor concentrations when ink is applied to the predeterminedlight-emitting cell, and two regions adjacent to a light-emitting cell,which is different from the predetermined light-emitting cell, may haveequal ink vapor concentrations when ink is applied to the light-emittingcell.

In the above-described organic light-emitting panel, the plurality oflight-emitting cells provided in each pixel may include a firstlight-emitting cell located at an end of the alignment, a secondlight-emitting cell located at a central portion of the alignment, and athird light-emitting cell located at another end of the alignment, eachorganic light-emitting layer being formed by applying, for each pixel,three types of ink, which correspond one-to-one to the different colorsof light, respectively to the three light-emitting cells in an order ofthe first light-emitting cell, the second light-emitting cell and thethird light-emitting cell, the plurality of pixels are arranged to becontinuously adjacent to each other, and in each pixel, two innersidewalls, which face each other in two adjacent banks defining thefirst light-emitting cell, have equal inclination angles, two innersidewalls, which face each other in two adjacent banks defining thesecond light-emitting cell, have different inclination angles, and twoinner sidewalls, which face each other in two adjacent banks definingthe third light-emitting cell, have equal inclination angles.

The above structure exerts an effect on the structure where anon-light-emitting cell is not provided between each pair of adjacentpixels and ink is applied in the order of the first light-emitting cell,the second light-emitting cell and the third light-emitting cell in eachpixel. That is to say, in the above structure, two inner sidewalls,which face each other in two adjacent banks defining the firstlight-emitting cell to which ink is applied in the first round, haveequal inclination angles, two inner sidewalls, which face each other intwo adjacent banks defining the second light-emitting cell to which inkis applied in the second round, have different inclination angles, andtwo inner sidewalls, which face each other in two adjacent banksdefining the third light-emitting cell to which ink is applied in thethird round, have equal inclination angles. With this structure, even inthe case where different ink vapor concentrations occur because ink isapplied to the light-emitting cells in sequence at different timings, itis possible to effectively prevent an uneven film thickness fromoccurring in the organic light-emitting layer formed in each of thefirst, second and third light-emitting cells by adjusting the relativepinning locations of the ink in the sidewalls of the banks.

In the above-described organic light-emitting panel, among two innersidewalls facing each other in two adjacent banks defining the secondlight-emitting cell, a sidewall of a bank located on a side of the thirdlight-emitting cell may have a larger inclination angle than a sidewallof a bank located on a side of the first light-emitting cell. With thisstructure, it is possible to prevent an uneven film thickness of theorganic light-emitting layer from occurring in each of the first, secondand third light-emitting cells.

In the above-described organic light-emitting panel, the sidewall of thebank located on the side of the first light-emitting cell among the twoinner sidewalls facing each other in the two adjacent banks defining thesecond light-emitting cell, and the two inner sidewalls facing eachother in the two adjacent banks defining the first light-emitting cell,may have equal inclination angles. With this structure, it is possibleto prevent an uneven film thickness of the organic light-emitting layerfrom occurring in each of the first, second and third light-emittingcells.

In the above-described organic light-emitting panel, the sidewall of thebank located on the side of the first light-emitting cell among the twoinner sidewalls facing each other in the two adjacent banks defining thesecond light-emitting cell, and the two inner sidewalls facing eachother in the two adjacent banks defining the third light-emitting cell,may have equal inclination angles. With this structure, it is possibleto prevent an uneven film thickness of the organic light-emitting layerfrom occurring in each of the first, second and third light-emittingcells.

In the organic light-emitting panel having the above structure, theinclination angles of the sidewalls of the banks can be set to thefollowing ranges:

(a1) among the two inner sidewalls facing each other in the two adjacentbanks defining the second light-emitting cell, the sidewall of the banklocated on the side of the third light-emitting cell has an inclinationangle of at least 35 degrees and at most 45 degrees,

(a2) among the two inner sidewalls facing each other in the two adjacentbanks defining the second light-emitting cell, the sidewall of the banklocated on the side of the first light-emitting cell has an inclinationangle of at least 25 degrees and at most 35 degrees,

(a3) each of the two inner sidewalls facing each other in the twoadjacent banks defining the first light-emitting cell has an inclinationangle of at least 25 degrees and at most 35 degrees, and

(a4) each of the two inner sidewalls facing each other in the twoadjacent banks defining the third light-emitting cell has an inclinationangle of at least 25 degrees and at most 35 degrees.

In the above-described organic light-emitting panel, the plurality oflight-emitting cells provided in each pixel may include a firstlight-emitting cell located at an end of the alignment, a secondlight-emitting cell located at a central portion of the alignment, and athird light-emitting cell located at another end of the alignment, eachorganic light-emitting layer being formed by applying, for each pixel,three types of ink, which correspond one-to-one to the different colorsof light, respectively to the three light-emitting cells in an order ofthe first light-emitting cell, the second light-emitting cell and thethird light-emitting cell, a non-light-emitting cell is provided betweeneach pair of adjacent pixels, a bank is provided between each pair of apixel and a non-light-emitting cell that are adjacent to each other, thebank separating the pixel from the non-light-emitting cell, and in eachpixel, two inner sidewalls, which face each other in two adjacent banksdefining the first light-emitting cell, have equal inclination angles,two inner sidewalls, which face each other in two adjacent banksdefining the second light-emitting cell, have different inclinationangles, and two inner sidewalls, which face each other in two adjacentbanks defining the third light-emitting cell, have different inclinationangles.

The above structure exerts an effect on the structure where anon-light-emitting cell is provided between each pair of adjacent pixelsand ink is applied in the order of the first light-emitting cell, thesecond light-emitting cell and the third light-emitting cell in eachpixel. That is to say, in the above structure, two inner sidewalls,which face each other in two adjacent banks defining the firstlight-emitting cell to which ink is applied in the first round, haveequal inclination angles, two inner sidewalls, which face each other intwo adjacent banks defining the second light-emitting cell to which inkis applied in the second round, have different inclination angles, andtwo inner sidewalls, which face each other in two adjacent banksdefining the third light-emitting cell to which ink is applied in thethird round, have different inclination angles. With this structure,even in the case where different ink vapor concentrations occur becauseink is applied to the light-emitting cells in sequence at differenttimings, it is possible to effectively prevent an uneven film thicknessfrom occurring in the organic light-emitting layer formed in each of thefirst, second and third light-emitting cells by adjusting the relativepinning locations of the ink in the sidewalls of the banks.

In the above-described organic light-emitting panel, among the two innersidewalls facing each other in the two adjacent banks defining thesecond light-emitting cell, the sidewall of the bank located on the sideof the third light-emitting cell may have a larger inclination anglethan the sidewall of the bank located on the side of the firstlight-emitting cell, and among the two inner sidewalls facing each otherin the two adjacent banks defining the third light-emitting cell, thesidewall of the bank located on the side of the non-light-emitting cellhas a larger inclination angle than the sidewall of the bank located onthe side of the second light-emitting cell. With this structure, it ispossible to prevent an uneven film thickness of the organiclight-emitting layer from occurring in each of the first, second andthird light-emitting cells.

In the above-described organic light-emitting panel, the sidewall of thebank located on the side of the third light-emitting cell among the twoinner sidewalls facing each other in the two adjacent banks defining thesecond light-emitting cell, and the sidewall of the bank located on theside of the non-light-emitting cell among the inner sidewalls facingeach other in the two adjacent banks defining the third light-emittingcell, may have equal inclination angles. With this structure, it ispossible to prevent an uneven film thickness of the organiclight-emitting layer from occurring in each of the first, second andthird light-emitting cells.

In the above-described organic light-emitting panel, the sidewall of thebank located on the side of the first light-emitting cell among the twoinner sidewalls facing each other in the two adjacent banks defining thesecond light-emitting cell, and the two inner sidewalls facing eachother in the two adjacent banks defining the first light-emitting cell,may have equal inclination angles. With this structure, it is possibleto prevent an uneven film thickness of the organic light-emitting layerfrom occurring in each of the first, second and third light-emittingcells.

In the above-described organic light-emitting panel, the sidewall of thebank located on the side of the second light-emitting cell among the twoinner sidewalls facing each other in the two adjacent banks defining thethird light-emitting cell, and the two inner sidewalls facing each otherin the two adjacent banks defining the first light-emitting cell, mayhave equal inclination angles.

In the organic light-emitting panel having the above structure, theinclination angles of the sidewalls of the banks can be set to thefollowing ranges:

(b1) among the two inner sidewalls facing each other in the two adjacentbanks defining the second light-emitting cell, the sidewall of the banklocated on the side of the third light-emitting cell has an inclinationangle of at least 35 degrees and at most 45 degrees,

(b2) among the two inner sidewalls facing each other in the two adjacentbanks defining the third light-emitting cell, the sidewall of the banklocated on the side of the non-light-emitting cell has an inclinationangle of at least 35 degrees and at most 45 degrees,

(b3) among the two inner sidewalls facing each other in the two adjacentbanks defining the second light-emitting cell, the sidewall of the banklocated on the side of the first light-emitting cell has an inclinationangle of at least 25 degrees and at most 35 degrees,

(b4) among the two inner sidewalls facing each other in the two adjacentbanks defining the third light-emitting cell, the sidewall of the banklocated on the side of the second light-emitting cell has an inclinationangle of at least 25 degrees and at most 35 degrees, and

(b5) each of the two inner sidewalls facing each other in the twoadjacent banks defining the first light-emitting cell has an inclinationangle of at least 25 degrees and at most 35 degrees.

In the above-described organic light-emitting panel, the plurality oflight-emitting cells provided in each pixel may include a firstlight-emitting cell located at an end of the alignment, a secondlight-emitting cell located at a central portion of the alignment, and athird light-emitting cell located at another end of the alignment, eachorganic light-emitting layer being formed by applying, for each pixel,three types of ink, which correspond one-to-one to the different colorsof light, respectively to the three light-emitting cells at the sametime, a non-light-emitting cell is provided between each pair ofadjacent pixels, a bank is provided between each pair of a pixel and anon-light-emitting cell that are adjacent to each other, the bankseparating the pixel from the non-light-emitting cell, and in eachpixel, two inner sidewalls, which face each other in two adjacent banksdefining the first light-emitting cell, have different inclinationangles, two inner sidewalls, which face each other in two adjacent banksdefining the second light-emitting cell, have equal inclination angles,and two inner sidewalls, which face each other in two adjacent banksdefining the third light-emitting cell, have different inclinationangles.

The above structure exerts an effect on the structure where anon-light-emitting cell is provided between each pair of adjacent pixelsand ink is applied at the same time to the first light-emitting cell,the second light-emitting cell and the third light-emitting cell in eachpixel. That is to say, since the ink is applied at the same time and anon-light-emitting cell is provided between each pair of adjacentpixels, two regions located on both sides of the second light-emittingcell (located at the central portion of the alignment) have equal inkvapor concentrations and two regions located on both sides of each ofthe first and third light-emitting cells have different ink vaporconcentrations, when ink is applied to the light-emitting cells. Basedon this state of ink vapor concentration distribution, in the abovestructure, two inner sidewalls, which face each other in two adjacentbanks defining the first light-emitting cell, have different inclinationangles, two inner sidewalls, which face each other in two adjacent banksdefining the second light-emitting cell, have equal inclination angles,and two inner sidewalls, which face each other in two adjacent banksdefining the third light-emitting cell, have different inclinationangles. With this structure, even in the case where different ink vaporconcentrations occur when ink is applied, it is possible to effectivelyprevent an uneven film thickness from occurring in the organiclight-emitting layer formed in each of the first, second and thirdlight-emitting cells by adjusting the relative pinning locations of theink in the sidewalls of the banks.

In the above-described organic light-emitting panel, among the two innersidewalls facing each other in the two adjacent banks defining the firstlight-emitting cell, the sidewall of the bank located on the side of thenon-light-emitting cell may have a larger inclination angle than thesidewall of the bank located on the side of the second light-emittingcell, and among the two inner sidewalls facing each other in the twoadjacent banks defining the third light-emitting cell, the sidewall ofthe bank located on the side of the non-light-emitting cell has a largerinclination angle than the sidewall of the bank located on the side ofthe second light-emitting cell. With this structure, it is possible toprevent an uneven film thickness of the organic light-emitting layerfrom occurring in each of the first, second and third light-emittingcells.

In the above-described organic light-emitting panel, the sidewall of thebank located on the side of the non-light-emitting cell among the twoinner sidewalls facing each other in the two adjacent banks defining thefirst light-emitting cell, and the sidewall of the bank located on theside of the non-light-emitting cell among the inner sidewalls facingeach other in the two adjacent banks defining the third light-emittingcell, may have equal inclination angles. With this structure, it ispossible to prevent an uneven film thickness of the organiclight-emitting layer from occurring in each of the first, second andthird light-emitting cells.

In the above-described organic light-emitting panel, the sidewall of thebank located on the side of the second light-emitting cell among the twoinner sidewalls facing each other in the two adjacent banks defining thefirst light-emitting cell, and the two inner sidewalls facing each otherin the two adjacent banks defining the second light-emitting cell, mayhave equal inclination angles. With this structure, it is possible toprevent an uneven film thickness of the organic light-emitting layerfrom occurring in each of the first, second and third light-emittingcells.

In the above-described organic light-emitting panel, the sidewall of thebank located on the side of the second light-emitting cell among the twoinner sidewalls facing each other in the two adjacent banks defining thethird light-emitting cell, and the two inner sidewalls facing each otherin the two adjacent banks defining the second light-emitting cell, mayhave equal inclination angles. With this structure, it is possible toprevent an uneven film thickness of the organic light-emitting layerfrom occurring in each of the first, second and third light-emittingcells.

In the organic light-emitting panel having the above structure, theinclination angles of the sidewalls of the banks can be set to thefollowing ranges:

(c1) among the two inner sidewalls facing each other in the two adjacentbanks defining the first light-emitting cell, the sidewall of the banklocated on the side of the non-light-emitting cell has an inclinationangle of at least 35 degrees and at most 45 degrees,

(c2) among the two inner sidewalls facing each other in the two adjacentbanks defining the third light-emitting cell, the sidewall of the banklocated on the side of the non-light-emitting cell has an inclinationangle of at least 35 degrees and at most 45 degrees,

(c3) among the two inner sidewalls facing each other in the two adjacentbanks defining the first light-emitting cell, the sidewall of the banklocated on the side of the second light-emitting cell has an inclinationangle of at least 25 degrees and at most 35 degrees,

(c4) among the two inner sidewalls facing each other in the two adjacentbanks defining the third light-emitting cell, the sidewall of the banklocated on the side of the second light-emitting cell has an inclinationangle of at least 25 degrees and at most 35 degrees, and

(c5) each of the two inner sidewalls facing each other in the twoadjacent banks defining the second light-emitting cell has aninclination angle of at least 25 degrees and at most 35 degrees.

In the above-described organic light-emitting panel, each inclinationangle may be an angle formed by a side wall of a bank and an uppersurface of the underlying layer on which the bank is provided.

In the above-described organic light-emitting panel, the underlyinglayer may include a TFT layer formed below the first layer, and in thepixel that is structured such that the two inner sidewalls facing eachother in the two adjacent banks defining the predeterminedlight-emitting cell have different inclination angles, the firstelectrode and the TFT layer may be electrically connected with eachother.

An organic display device according to another aspect of the presentinvention includes any one of the above organic light-emitting panelsaccording to an aspect of the present invention. Therefore, the organicdisplay device according to another aspect of the present invention, asdescribed above, can prevent the organic light-emitting layer in theorganic light-emitting panel from becoming uneven in film thickness andprovide excellent light-emitting characteristics.

A manufacturing method of an organic light-emitting panel according to afurther aspect of the present invention is a manufacturing method of anorganic light-emitting panel including an array of a plurality of pixelsand the manufacturing method comprises the following steps:

(first step) forming, on a substrate, an underlying layer including aplurality of first electrodes;

(second step) layering a photoresist material on the underlying layer;

(third step) forming, for each pixel, a plurality of openingscorresponding to a plurality of light-emitting cells by performing anexposure with a mask laid on the layered photoresist material to form apattern, and forming a plurality of banks to define each light-emittingcell by separating the light-emitting cells one from another;

(fourth step) forming a plurality of organic light-emitting layers bydripping ink that includes organic light-emitting materials into theplurality of openings corresponding to the plurality of light-emittingcells, and drying the ink; and

(fifth step) forming a second electrode above each organiclight-emitting layer.

In the manufacturing method of an organic light-emitting panel accordingto a further aspect of the present invention, in the third step, atleast one pixel among the plurality of pixels is formed such that twoinner sidewalls, which face each other in two adjacent banks defining apredetermined light-emitting cell among the plurality of light-emittingcells, have different inclination angles.

With the above manufacturing method of the organic light-emitting panelwhere two inner sidewalls, which face each other in two adjacent banksdefining the predetermined light-emitting cell among the plurality oflight-emitting cells, have different inclination angles, it is possibleto adjust the pinning locations of the ink dripped during themanufacturing. To be more specific, the larger the inclination angle ofa sidewall of a bank is, the higher the pinning location is; and thesmaller the inclination angle of a sidewall of a bank is, the lower thepinning location is.

In the above manufacturing method of an organic light-emitting panelaccording to a further aspect of the present invention, it is possibleto prevent the organic light-emitting layer in each light-emitting cellfrom becoming uneven in film thickness, based on the relationship thatthe film thickness of the organic light-emitting layer and theinclination angle of the bank sidewall have a reverse relationship afterthe ink is dried. It is thus possible to manufacture an organiclight-emitting panel with excellent light-emitting characteristics.

In the above manufacturing method of an organic light-emitting panelaccording to a further aspect of the present invention, in the thirdstep, the at least one pixel may be formed such that two innersidewalls, which face each other in two adjacent banks defining alight-emitting cell other than the predetermined light-emitting cell,have equal inclination angles.

When the above structure is adopted, two inner sidewalls, which faceeach other in two adjacent banks defining the predeterminedlight-emitting cell, are formed to have different inclination angles. Itis thus possible to form the organic light-emitting layer having an evenfilm thickness in each light-emitting cell, and manufacture the organiclight-emitting panel having excellent light-emitting characteristics, asdescribed above. In addition, with the above-described structure where,in each of one or more light-emitting cells other than the predeterminedlight-emitting cell in the pixel, two inner sidewalls facing each otherhave equal inclination angles, it is possible to prevent the organiclight-emitting layer from becoming uneven in film thickness and provideexcellent light-emitting characteristics. This makes it possible tomanufacture an organic light-emitting panel having excellentlight-emitting characteristics in all pixels.

Note that the term “equal” above does not mean exact mathematicalequivalence, but rather takes factors such as dimensional error duringmanufacturing of the display device into account. Specifically, the term“equal” refers to making the inclination angles equal within the rangepermitted in practice by the difference in luminous efficiency (unevenluminance) between the light-emitting cells in the central region andperipheral region of the panel.

In the above manufacturing method of an organic light-emitting panelaccording to a further aspect of the present invention, in the thirdstep, when the exposure of the photoresist material is performed, thetwo inner sidewalls facing each other in the two adjacent banks definingthe predetermined light-emitting cell may be formed to have differentinclination angles, by causing portions of the photoresist materialcorresponding to the sidewalls of the banks defining the predeterminedlight-emitting cell to be exposed to different amounts of light. Withthe above structure where the two inner sidewalls facing each other inthe two adjacent banks defining the predetermined light-emitting cellare formed to have different inclination angles, by causing portions ofthe photoresist material corresponding to the sidewalls of the banksdefining the predetermined light-emitting cell to be exposed todifferent amounts of light, it is possible to form the organiclight-emitting layer having an even film thickness in eachlight-emitting cell, by adjusting the pinning location. This makes itpossible to manufacture an organic light-emitting panel having excellentlight-emitting characteristics.

In the above manufacturing method of an organic light-emitting panelaccording to a further aspect of the present invention, in the thirdstep, when the exposure of the photoresist material is performed, thetwo inner sidewalls facing each other in the two adjacent banks definingthe predetermined light-emitting cell may be formed to have differentinclination angles, by using masks that are different in lighttransmissivity at portions of the photoresist material corresponding tothe sidewalls of the banks defining the predetermined light-emittingcell. With the above structure where the two inner sidewalls facing eachother in the two adjacent banks defining the predeterminedlight-emitting cell are formed to have different inclination angles, bycausing portions of the photoresist material corresponding to thesidewalls of the banks defining the predetermined light-emitting cell tobe exposed to different amounts of light, it is also possible to formthe organic light-emitting layer having an even film thickness in eachlight-emitting cell, by adjusting the pinning location. This makes itpossible to manufacture an organic light-emitting panel having excellentlight-emitting characteristics.

In the above manufacturing method of an organic light-emitting panelaccording to a further aspect of the present invention, in the thirdstep, after the photoresist material is exposed and developed, the twoinner sidewalls facing each other in the two adjacent banks defining thepredetermined light-emitting cell may be formed to have differentinclination angles, by additionally performing an exposure process ontoa portion of the photoresist material corresponding to one of the twoinner sidewalls facing each other in the two adjacent banks defining thepredetermined light-emitting cell. The organic display device obtainedin this way produces the same advantageous effect as the organiclight-emitting panel manufactured by the manufacturing method of thepresent invention. With the above structure where the two innersidewalls facing each other in the two adjacent banks defining thepredetermined light-emitting cell are formed to have differentinclination angles, by causing portions of the photoresist materialcorresponding to the sidewalls of the banks defining the predeterminedlight-emitting cell to be exposed to different amounts of light, it isalso possible to form the organic light-emitting layer having an evenfilm thickness in each light-emitting cell, by adjusting the pinninglocation. This makes it possible to manufacture an organiclight-emitting panel having excellent light-emitting characteristics.

An organic display device according to a still further aspect of thepresent invention includes an organic light-emitting panel manufacturedby any one of the above-described manufacturing methods of the presentinvention. The organic display device including the organiclight-emitting panel manufactured by the above manufacturing method, asdescribed above, can prevent the organic light-emitting layer in theorganic light-emitting panel from becoming uneven in film thickness andprovide excellent light-emitting characteristics.

Embodiment

The following describes an example of an embodiment of the presentinvention with reference to the drawings.

Note that the following Embodiment is simply an example to clearlyillustrate a structure of the present invention and the acts and effectsthereof. The present invention is in no way limited to the followingEmbodiment except in its essential characteristic elements.

(Process by which the Embodiment According to the Present Invention wasAchieved)

As a result of intense study, the inventor of the present inventiondiscovered the following with regard to the organic light-emitting panelrecited in the Background Art and the organic display device providedwith the organic light-emitting panel.

Typically, as shown in FIG. 25A, an anode 902 and an electrode coatinglayer 903 covering the anode 902 are formed on a substrate 901, for eachof sub-pixels 900 a, 900 b, and 900 c. A hole injection layer 904 isthen formed to cover the entire surface of the electrode coating layer903 and the substrate 901, and on the hole injection layer 904, organiclight-emitting layers 906 a, 906 b, and 906 c of different colors areformed one-to-one in sub-pixels 900 a, 900 b, and 900 c. The organiclight-emitting layers 906 a, 906 b, and 906 c are separated from eachother by banks 905 a to 905 d formed to stand on the hole injectionlayer 904.

As shown in FIG. 25A, in an organic light-emitting panel of aconventional technology, an uneven film thickness is observed in theorganic light-emitting layer 906 b of the sub-pixel 900 b that islocated in a central region of the array. Specifically, the followingphenomenon occurs. That is to say, the surface level of the organiclight-emitting layer 906 b is higher at location C₃ in the bank 905 cthan at location C₂ in the bank 905 b. Also, the surface level of theorganic light-emitting layer 906 b is higher than the surface level ofthe organic light-emitting layer 906 a at location C₁ in the bank 905 b.

Also, as another example, as shown in FIG. 25B, a phenomenon occurs inwhich the surface levels of the organic light-emitting layers 956 b and956 c in the sub-pixels 950 b and 950 c at locations C₁₂ and C₁₄ in thebanks 955 c and 955 d are higher than the surface levels of the organiclight-emitting layers 956 b and 956 c at locations C₁₁ and C₁₃ in thebanks 955 b and 955 c, respectively. Note that, as shown in FIG. 25B,the surface levels of the organic light-emitting layer 956 a in thesub-pixel 950 a at respective locations in the bank 955 a and the bank955 b are approximately the same, and a large amount of unevenness infilm thickness is not observed.

After repeated examination of the above phenomenon, the inventordetermined that reduction in uniformity of film thickness in the organiclight-emitting layer causes a non-uniform vapor concentrationdistribution during ink drying, as described below. That is to say, asshown in FIG. 26A, suppose a state in which ink 9060 c for forming theorganic light-emitting layer has been applied in an area between thebank 905 b and the bank 905 c, and the right-hand side of FIG. 26A islower than the left-hand side in vapor concentration distribution asindicated by the two-dot chain line. In this case, the film thickness inthe organic light-emitting layer becomes uneven for the followingreasons.

As shown in FIG. 26A, a surface profile L₉₀ of ink 9060 b has beenswollen up in the central region of the sub-pixel immediately after theink 9060 b is dripped. When drying the ink, due to the non-uniform vaporconcentration distribution as mentioned above, the evaporation ratevaries in reverse proportion to the vapor concentration, and thereforeit can be theoretically considered that the ink changes to have asurface profile L₉₁.

However, as shown in FIG. 26B, solvent in the ink 9061 b flows duringdrying as shown by the dotted-line arrow L₉₂. This is because solventflows to compensate for solvent that has evaporated (i.e. flows tominimize surface free energy), and along with the flow of the solvent,the solute (organic light-emitting material) also flows. Therefore, asshown in FIG. 26C, if the vapor concentration distribution is notuniform, the organic light-emitting layer 906 b is formed to have asurface profile L₉₃ in which the closer to the right-hand side the layeris, the higher the layer is.

The inventor therefore deduced that, in an organic light-emitting panel,uniformity of film thickness of the organic light-emitting layerdecreases due to non-uniformity of vapor concentration distributionduring ink drying.

The inventor also discovered technology to vary, within the panel, thepinning location of ink on a bank side wall by varying the inclinationangle of the bank side wall, which improves uniformity of film thicknessin the organic light-emitting layer.

Embodiment 1

1. Configuration of Display Device 1

The overall structure of the display device 1 according to the presentEmbodiment is described with reference to FIG. 1.

As shown in FIG. 1, the display device (organic display device) 1includes a display panel unit 10 and a drive control unit 20 connectedto the display panel unit 10. The display panel unit 10 is an organiclight-emitting panel that uses the phenomenon of electroluminescenceoccurring in organic material and is composed of a plurality of pixelsarrayed two-dimensionally in the X-Y plane direction.

The drive control unit 20 is composed of four drive circuits 21-24 and acontrol circuit 25.

Note that in an actual display device 1, the placement of the drivecontrol unit 20 with respect to the display panel unit 10 is not limitedin this way.

2. Structure of Display Panel 10

The structure of the display panel 10 is described with reference toFIG. 2. Note that, as an example, the display panel 10 in the presentEmbodiment is a top emission type organic light-emitting panel includinga plurality of pixels arranged in a matrix, each pixel includingsub-pixels that are each provided with an organic light-emitting layerhaving a luminescent color of either red (R), green (G), or blue (B).FIG. 2 depicts one sub-pixel 100 in a pixel.

As shown in FIG. 2, in the display panel 10, anodes 102 are formed abovea TFT substrate (hereinafter simply referred to as a “substrate”) 101 inone-to-one correspondence with the sub-pixels 300 a, 300 b and 300 c,and on each of the anodes 102, an electrode coating layer 103 is formed,and a hole injection transporting layer 104 is layered on the electrodecoating layers 103.

Above the hole injection transporting layer 104, banks 105, made ofinsulating material, are provided to stand to separate the sub-pixels100 from each other. An organic light-emitting layer 106 is formed inthe region in each sub-pixel 100 separated by the banks 105, and anelectron injection layer 107, cathode 108, and passivation layer 109 arelayered above the organic light-emitting layer 106 in this order.

a) Substrate 101

The substrate 101 is made of a base of an insulating material such asalkali-free glass, soda glass, non-fluorescent glass, phosphate glass,borate glass, quartz, acrylic resin, styrenic resin, polycarbonateresin, epoxy resin, polyethylene, polyester, silicone resin, alumina,etc. Although not illustrated, in the substrate 101, a TFT layer, apassivation film, an interlayer insulation film, etc. are laminated.

b) Anode 102

The anode 102 is composed of a single layer or of a laminate of aplurality of layers, either being made of a conductive material, such asaluminum (Al), alloy including Al, silver (Ag), alloy of silver,palladium, and copper (APC), alloy of silver, rubidium, and gold (ARA),alloy of molybdenum and chromium (MoCr), alloy of nickel and chromium(NiCr), etc. Note that in the case of a top emission type panel such asthe panel in the Embodiment, it is preferable that the anode 102 be madeof a highly reflective material.

c) Electrode Coating Layer 103

The electrode coating layer 103 is made of, for example, indium tinoxide (ITO) and covers at least a part of the top surface the anode 102in the Z axis direction.

d) Hole Injection Transporting Layer 104

The hole injection transporting layer 104 is a layer formed from anoxide of a metal such as silver (Ag), molybdenum (Mo), chromium (Cr),vanadium (V), tungsten (W), nickel (Ni), or iridium (Ir), or formed froma conductive polymer material, such as PEDOT (a mixture of polythiopheneand polystyrene sulfonate). The hole injection transporting layer 104formed from such a metal oxide, among the above materials, has thefunction of assisting with generation of holes and injecting andtransporting the holes stably into the organic light-emitting layer 106.The hole injection transporting layer 104 has a high work function.

When the hole injection transporting layer 104 is made of an oxide of atransition metal, a plurality of levels can be occupied since there area plurality of oxidation numbers. This makes hole injection easy andallows for reduction of driving voltage.

e) Banks 105

The banks 105 are made of an organic material such as resin and haveinsulating properties. Examples of the organic material used to form thebanks 105 include acrylic resin, polyimide resin, novolac-type phenolicresin, etc. It is also preferable that the banks 105 have organicsolvent resistance.

Furthermore, since the banks 105 are etched and baked when formed, it ispreferable that the banks be made of a highly resistant material thatwill not change in shape or quality during the etching and bakingprocesses. To provide the banks with liquid repellency, the sidewallscan be fluoridated.

Note that as the insulating material used in forming the banks 105, anyliquid repellent material with a resistivity of 10⁵ Ω·cm can be used,starting with the above materials. Using a material with a resistivityof less than 10⁵ Ω·cm leads to production of leak current between theanode 102 and the cathode 108, or between adjacent sub-pixels 100, whichcauses a variety of problems such as increased power consumption.

Furthermore, if a hydrophilic material is used to form the banks 105,the difference in affinity/liquid repellency between the sidewall of thebanks 105 and the surface of the hole injection transporting layer 104becomes small, and it thus becomes difficult to selectively maintain theink, which includes an organic substance for forming the organiclight-emitting layer 106, at the opening of the banks 105.

The structure of the banks 105 need not be a single layer as shown inFIG. 2, but may adopt a multi-layered structure composed of two or morelayers. In such a case, the above materials may be combined for eachlayer, or layers may alternate between non-organic and organic material.

F) Organic Light-Emitting Layer 106

The organic light-emitting layer 106 has a function to emit light whenan excitation state is produced by the recombination of holes injectedthrough the anode 102 with electrons injected through the cathode 108.The material used to form the organic light-emitting layer 106 needs tobe a light-emitting organic material, a film of which can be formed bywet printing.

More specifically, it is preferable that the organic light-emittinglayer 106 be made of a fluorescent material such as an oxinoid compound,perylene compound, coumarin compound, azacoumarin compound, oxazolecompound, oxadiazole compound, perinone compound, pyrrolo-pyrrolecompound, naphthalene compound, anthracene compound, fluorene compound,fluoranthene compound, tetracene compound, pyrene compound, coronenecompound, quinolone compound and azaquinolone compound, pyrazolinederivative and pyrazolone derivative, rhodamine compound, chrysenecompound, phenanthrene compound, cyclopentadiene compound, stilbenecompound, diphenylquinone compound, styryl compound, butadiene compound,dicyanomethylene pyran compound, dicyanomethylene thiopyran compound,fluorescein compound, pyrylium compound, thiapyrylium compound,selenapyrylium compound, telluropyrylium compound, aromatic aldadienecompound, oligophenylene compound, thioxanthene compound, anthracenecompound, cyanine compound, acridine compound, metal complex of an8-hydroxyquinoline compound, metal complex of a 2-bipyridine compound,complex of a Schiff base and a group three metal, metal complex ofoxine, rare earth metal complex, etc., as recited in Japanese PatentApplication Publication No. H5-163488.

g) Electron Injection Layer 107

The electron injection layer 107 has a function to transport electronsinjected through the cathode 108 to the organic light-emitting layer 106and is preferably made of, for example, barium, phthalocyanine, lithiumfluoride, or a combination thereof.

h) Cathode 108

The cathode 108 is made of, for example, ITO, indium zinc oxide (IZO),etc. When the display panel 10 is a top-emission type, it is preferablethat the cathode 108 be made of a light-transmissive material. It ispreferable that the light transmissivity be 80% or greater.

The material used to form the cathode 108 may be, in addition to theabove materials, for example, an alkali metal, alkali earth metal, or alaminate structure having, in the following order, a layer that includesa halide of an alkali metal or alkali earth metal and a layer thatincludes silver. The layer that includes silver may be made of silveralone, or from a silver alloy. Also, in order to increase lightextraction efficiency, a highly-transparent refraction index adjustmentlayer may be provided above the layer that includes silver.

i) Passivation Layer 109

The passivation layer 109 has a function to control the organiclight-emitting layer 106 or other layers from being exposed to water orair and is made of, for example, silicon nitride (SiN), siliconoxynitride (SiON) etc. When the display panel 10 is a top-emission type,it is preferable that the passivation layer 109 be made of alight-transmissive material.

3. Structure of Banks 105

As shown in FIG. 3, in the display panel 10 of the present Embodiment,the banks 105 are arranged in lines, as one example. More specifically,the banks 105 each extend along the Y axis and separate the adjacentsub-pixels 100 in the X axis direction. The sub-pixels 100 are formed sothat each of the regions separated by the banks 105 in each pixel emitsa different color. For example, one pixel is composed of threesub-pixels that emit light of red (R), green (G), and blue (B),respectively.

4. Structure of Banks 105 in Each Region

The structure of the banks 105 in each region is described withreference to FIG. 4. Note that FIG. 4 is a schematic cross-sectionalview taken along line A-A′ passing through the display panel 10 in FIG.1, and schematically illustrating some parts thereof.

As shown in FIG. 4, sub-pixels 100 a, 100 b, and 100 c are arrangedcontinuously in this order from left to right along the X axisdirection. Note that in the display panel 10 of the present embodiment,the sub-pixels are arranged to be continuously adjacent to each other.

The sub-pixel 100 a is defined by banks 105 a and 105 b; the sub-pixel100 b is defined by banks 105 b and 105 c; and the sub-pixel 100 c isdefined by banks 105 c and 105 d. Sidewalls 105 aa, 105 ba, 105 bb, 105cb, 105 cc, and 105 dc of the banks 105 a, 105 b, 105 c and 105 drespectively form angles θaa, θba, θbb, θcb, θcc, and θdc with thesurface of the hole injection transporting layer 104, which is anunderlying layer.

In the present Embodiment, the angles θaa, θba, θbb, θcb, θcc, and θdcsatisfy the relationships indicated by the following expressions.

θcb>θaa=θba=θbb=θcc=θde  [Expression 1]

Note that in the present Embodiment, it is preferable that the anglesθaa, θba, θbb, θcb, θcc, and θde satisfy the relationships indicated bythe above Expression 1 and are set to the following ranges.

25°<θaa=θba=θbb=θcc=θde<35°  [Expression 2]

35°<θcb<45°  [Expression 3]

5. Relationship Between Inclination Angle θ of Sidewall of Banks 105 andFilm Thickness of Organic Light-Emitting Layer 106

The relationship between the inclination angles θ of the sidewalls ofthe banks 105 and the film thickness of the organic light-emitting layer106 is described with reference to FIGS. 5 and 6. Note that FIG. 5 is aschematic rendering of the structure of a sub-pixel.

As shown in FIG. 5A, the inclination angle of the sidewall of bank 105 x(the angle formed between the sidewall and the surface of the holeinjection transporting layer 104) is represented by angle θx, and asshown in FIG. 5B, the inclination angle of the sidewall of bank 105 y(the angle formed between the sidewall and the surface of the holeinjection transporting layer 104) is represented by angle θy. Here, theangles θx and θy satisfy the following relationship.

θy>θx  [Expression 4]

When ink 1060 x and ink 1060 y, which include an organic light-emittingmaterial, are each dripped into the openings defined by the banks 105 xand 105 y, respectively, the pinning locations Px and Py respectivelyhave heights Hx and Hy that satisfy the following relationship.

Hy>Hx  [Expression 5]

As shown in FIG. 5C, after drying the ink 106θx, the height Hx of thepinning location Px is relatively low, which causes the organiclight-emitting layer 106 x to swell at the central portion of thesub-pixel to a film thickness of Tx.

On the other hand, as shown in FIG. 5D, after drying the ink 1060 y, theheight Hy of the pinning location Py is relatively high, which causesthe organic light-emitting layer 106 y to sag at the central portion ofthe sub-pixel to a film thickness of Ty.

The thicknesses Tx and Ty satisfy the following relationship.

Tx>Ty  [Expression 6]

FIG. 6 summarizes the above relationships. As shown in FIG. 6, as theinclination angle (taper angle) θ of the bank 105 grows smaller, thepinning height H lowers, and as a result, the film thickness T of theorganic light-emitting layer 106 becomes thicker. Conversely, as theinclination angle (taper angle) 0 of the bank 105 grows larger, thepinning height H becomes higher, and as a result, the film thickness Tof the organic light-emitting layer 106 becomes thinner.

Based on the above factors, five samples were created and evaluated.FIGS. 7 and 8 show the results.

As shown in FIGS. 7 and 8, as compared to the distribution of filmthickness of sample 2, the pinning location is higher in samples 3 and4, which have a larger taper angle. Note that in FIGS. 7 and 8, thehorizontal axis represents the horizontal direction, and the verticalaxis represents the direction of height.

In sample 5, however, in which the bank has a taper angle (inclinationangle) of 50°, the film thickness is less uniform than in sample 2.

6. Manufacturing Method of Display Panel 10

The following describes the characteristic processes of themanufacturing method of the display panel 10 according to the presentEmbodiment with reference to FIGS. 9 and 10. Note that with regard tothe manufacturing processes that are omitted in the followingdescription, any of the variety of processes suggested by conventionaltechnologies may be used.

First, as shown in FIG. 9A, above the substrate 101 in the direction ofthe Z axis, anodes 102 and electrode coating layers 103 are layered inthis order in regions in which sub-pixels 1000 a, 1000 b, and 1000 c areto be formed. Furthermore, A hole injection transporting layer 104 isthen layered thereon so as to cover the entire surface. The anodes 102is formed, for example, by first forming a thin film made of Al or Alalloy or a thin Ag film by the sputtering method or vacuum depositionmethod and then patterning the thin Ag film by the photolithographymethod.

The electrode coating layers 103 is formed, for example, by forming athin ITO film on the surface of the anodes 102 using a method such asthe sputtering method and then patterning the thin ITO film by a methodsuch as photolithography. To form the hole injection transporting layer104, first a metal film is formed on the surface of the substrate 101,including the surface of the electrode coating layer 103, by a methodsuch as the sputtering method. Subsequently, the metal film is oxidizedto form the hole injection transporting layer 104.

Next, as shown in FIG. 9B, the spin coat method, for example, is used toform a bank material layer 1050 so as to cover the top of the holeinjection transporting layer 104. A photoresist material is used to formthe bank material layer 1050. Specifically, as described above, anorganic material having insulating properties such as acrylic resin,polyimide resin, novolac-type phenolic resin, etc. can be used.

Subsequently, as shown in FIG. 9C, a mask 501 is placed above the bankmaterial layer 1050, the mask 501 having openings 501 a, 501 b, 501 c,and 501 d at the locations for forming the banks. In this state,exposure is performed via the openings 501 a, 501 b, 501 c, and 501 d ofthe mask 501.

Note that, as shown in FIG. 9C, in the mask 501, a width Wa of theopening 501 a located on the left-hand side of a region 1000 a in whicha sub-pixel is to be formed (hereinafter, such a region is referred toas “planned sub-pixel formation region”), is defined by points Pa1 andPa2 positioned at the foots of the sidewalls 105 aa, . . . of the bank105 a that is to be formed (see FIG. 4).

On the other hand, a width Wc1 of the opening 501 c located between theplanned sub-pixel formation regions 1000 b and 1000 c is defined by apoint Pc1 being at the upper edge of the sidewall 105 cb of the bank 105c that is to be formed (see FIG. 4) and a point Pc2 being at the foot ofthe sidewall 105 cc of the bank 105 c that is to be formed (see FIG. 4).

Next, as shown in FIG. 10A, a mask 502 is placed above the bank materiallayer 1050, the mask 502 having opening 502 c at the locationcorresponding to the sidewall 105 cb of the bank 105 c (see FIG. 4). Inthis state, the second exposure is performed via the opening 502 c ofthe mask 502.

Note that, as shown in FIG. 10A, in the mask 502, a width Wc2 of theopening 502 c is defined by points Pc3 and Pc1 being at the foot and theupper edge of the sidewall 105 cb of the bank 105 c that is to beformed.

Next, the development and baking are performed to form the banks 105 a,105 b, 105 e, and 105 d as shown in FIG. 10B. As described above, thesidewall 105 cb of the bank 105 c on the planned sub-pixel formationregion 1000 b side is larger than the sidewalls 105 aa, 105 ba, 105 bb,and 105 dc of the banks 105 a, 105 b and 105 d and the sidewall 105 ccof the bank 105 c on the planned sub-pixel formation region 1000 c side.

After this, as shown in FIG. 10C, ink 1060 a including an organiclight-emitting material is applied to an opening (the planned sub-pixelformation region 1000 a) defined by the banks 105 a and 105 b by theinkjet method or the like.

Subsequently, as shown in FIG. 11A, ink 1060 b including an organiclight-emitting material is applied to an opening (the planned sub-pixelformation region 1000 b) defined by the banks 105 b and 105 c by theinkjet method or the like. Here, since, as described above, theinclination angle of the sidewall 105 cb of the bank 105 c is set to belarger than the inclination angles of the other sidewalls, the pinninglocation Qcb of the ink 1060 b in the sidewall 105 cb of the bank 105 cbecomes higher in position than the other pinning locations Qaa, Qba,and Qbb.

Subsequently, as shown in FIG. 11B, ink 1060 c including an organiclight-emitting material is applied to an opening (the planned sub-pixelformation region 1000 c) defined by the banks 105 c and 105 d by theinkjet method or the like. Here, since ink has already been applied tothe planned sub-pixel formation region adjacent, on the right-hand side,to the bank 105 d, two ends of the applied ink 1060 c in the X axisdirection have the same ink vapor concentration, and the organiclight-emitting layer has even film thickness without adjustment of theinclination angles of the sidewalls of the banks. This is clear from theabove.

Note that, although not illustrated, subsequently the ink is dried, andthe electron injection layer 107, cathode 108, passivation layer 109,etc, are layered in this order to form the display panel 10.

7. Ink Applying Process and Drying Process

The following describes the relationships between the ink applyingprocess and the ink drying process with reference to FIGS. 12A and 12B.

As illustrated in FIG. 12A, in the present embodiment, firstly red ink(the ink 1060 a) is applied (step S1), then green ink (the ink 1060 b)is applied (step S2), and blue ink (the ink 1060 c) is applied (stepS3). After this, ink drying process is performed to dry all the appliedinks at once (step S4).

As an alternative to the above method, as illustrated in FIG. 12B, thefollowing processes may be performed in sequence in the stated order:applying red ink (the ink 1060 a) (step S11) and drying the applied redink (step S12); applying green ink (the ink 1060 b) (step S21) anddrying the applied green ink (step S22); and applying blue ink (the ink1060 c) (step S31) and drying the applied blue ink (step S32). In thiscase, the relationships in inclination angle among the side walls 105aa, 105 ba, 105 bb, 105 cb, 105 cc, and 105 dc of the banks 105 a, 105b, 105 c, and 105 d may be the same as those described above. Thisstructure also can restrict the film thickness of the formed organiclight-emitting layer 106 from becoming uneven.

8. Advantageous Effects

As shown in FIG. 4, in the display panel 10 of the display device 1according to the present Embodiment, inclination angle θcb of thesidewall 105 cb of the bank 105 c positioned on the sub-pixel 100 c sideis set larger than the inclination angles θaa, θba, θbb, θcc, and θdc ofother sidewalls 105 aa, 105 ba, 105 bb, 105 cc, and 105 dc. As a result,as shown in FIG. 11A, when the ink 1060 b is applied in the plannedsub-pixel formation region 1000 b, the pinning location Qcb is higher inposition than the other pinning locations Qaa, Qba, and Qbb.

On the other hand, the inclination angles θaa, θba, θbb, θcc, and θdc ofthe other sidewalls 105 aa, 105 ba, 105 bb, 105 cc, and 105 dc areequal.

This enables sub-pixels 100 a, 100 b, and 100 c to have a uniform filmthickness in the organic light-emitting layer 106 of the display panel10 after drying, which produces an advantageous effect of having littleluminance unevenness.

Note that, by using the manufacturing method of the display device 1 inthe present Embodiment, which has been described with reference to FIGS.9, 10, and 11, the display device 1 having the above advantageous effectcan be manufactured.

Also, the term “equal” does not necessarily mean that the targets arecompletely equal with each other in numerical value, but includes, forexample, a measurement error in manufacturing of the display device 1.More specifically, it is suggested that, in the display panel 10, theinclination angles are recognized as being equal as far as thedifference in luminous efficiency (luminance unevenness) betweensub-pixels 100 a, 100 b, and 100 c, which correspond to the inclinationangles, fails in an acceptable range.

[Modification 1]

Next, with reference to FIG. 13, Modification 1 of the manufacturingmethod of the display device 1 is described. FIG. 13 illustratesprocesses corresponding to processes illustrated in FIGS. 9C to 10A.

As shown in FIG. 13, first a bank material layer 1050 is formed to coverthe hole injection transporting layer 104, and then a mask 503 is placedabove the bank material layer 1050. The mask 503 is provided with lighttransmissive portions 503 a, 503 b, 503 c 1, 503 c 2, and 503 d. Thelight transmissive portions 503 a, 503 b, 503 c 1, 503 c 2, and 503 dare provided at locations corresponding to portions in which the banks105 a, 105 b, 105 c, and 105 d are to be formed.

In the manufacturing method of the display device 1 in Modification 1,width Wa of the light transmissive portion 503 a, which corresponds tothe left-hand side of the planned sub-pixel formation region 1000 a, isdefined by points Pa1 and Pa2 at the feet of the sidewalls 105 aa, . . .of the bank 105 a (see FIG. 4) that is to be formed.

On the other hand, width Wc2 of the light transmissive portion 503 c 1,which corresponds to a region between the planned sub-pixel formationregions 1000 b and 1000 c, is defined by points Pc2 and Pc1 that arerespectively positioned at the foot and upper edge of the bank 105 c tobe formed (see FIG. 4). Also, the light transmissive portion 503 c 2 isdefined by points Pc3 and Pc1 that are respectively positioned at thefoot and upper edge of the sidewall 105 cb of the bank 105 c to beformed (see FIG. 4).

The mask 503 is made from a half-tone or the like, and the lighttransmissive portions 503 a, 503 b, 503 c 1, and 503 d differ from thelight transmissive portion 503 c 2 in light transmissivity. Morespecifically, the light transmissive portion 503 c 2 is larger than thelight transmissive portions 503 a, 503 b, 503 c 1, and 503 d in lighttransmissivity.

In the state where the mask 503 having the above structure is set inplace, the exposure and development, and then baking are performed toform the banks 105 a, 105 b, 105 c, and 105 d as shown in FIG. 10B. Thatis to say, sidewalls having larger inclination angles are formed atlocations which are exposed to light via the light transmissive portion503 c 2 having a larger light transmissivity than the light transmissiveportions 503 a, 503 b, 503 c 1, and 503 d, in accordance with therelationship indicated by the above-described Expression 1.

Note that subsequent processes are the same as those in the aboveEmbodiment.

The display device 1 can be manufactured by the above manufacturingmethod as well.

[Modification 2]

Next, with reference to FIGS. 14A to 15B, Modification 2 of themanufacturing method of the display device 1 is described. FIGS. 14A to15B illustrate processes corresponding to the processes illustrated inFIGS. 9C to 10B.

As shown in FIG. 14A, first a bank material layer 1050 is formed tocover the hole injection transporting layer 104, and then a mask 504 isplaced above the bank material layer 1050. The mask 504 has openings 504a, 504 b, 504 c, and 504 d corresponding to the portions at which banks105 are to be formed.

The openings 504 a, 504 b, and 504 d are formed to have the same widthas the opening 501 a in the mask 501 used in the manufacturing method ofthe above Embodiment.

On the other hand, a width Wc3 of the opening 504 c located between theplanned sub-pixel formation regions 1000 b and 1000 d in correspondencewith the bank 105 c that is to be formed (see FIG. 4) is set to belarger than a width that is defined by points Pc3 and Pc2 being at thefeet of the bank 105 c that is to be formed (see FIG. 4), as indicatedby the two-dot chain line in FIG. 14A. More specifically, the width ismade larger at the portions where the inclination angles are to belarger.

In the state where the mask 504 is set in place as shown in FIG. 14A,the exposure and development in the first round are performed. Afterthis process is performed, as shown in FIG. 14B, bank material layers1051 a, 1051 b, 1051 c, and 1051 d remain in the locations correspondingto the openings 504 a, 504 b, 504 c, and 504 d.

Note that, as shown in FIG. 14B, the inclination angles of the sidewallsin the bank material layers 1051 a, 1051 b, 1051 c, and 1051 d areuniform after the first exposure and development are performed. InModification 2, the baking is not performed at this point in time.

As shown in FIG. 15A, a mask 505 is placed above the bank materiallayers 1051 a, 1051 b, 1051 c, and 1051 d after they are formed. In themask 505, an opening 505 c is provided only at the location where theinclination angle is to be larger (sidewall 105 cb of the bank 105 c)among the locations in the mask 505 corresponding to the sidewalls ofthe banks 105 a, 105 b, 105 c, and 105 d that are to be formed.

In the state where the mask 505 is set in place, the exposure anddevelopment in the second round are performed, and then the baking isperformed to form the banks 105 a, 105 b, 105 c, and 105 d as shown inFIG. 15B.

Subsequently, the display device 1 can be manufactured by performing thesame processes as in the above Embodiment or the like.

[Verification of Manufacturing Method]

Using a concrete example, the shape of the banks after formation wasverified for the manufacturing methods of the above Embodiment andModifications 1 and 2. The results are described with reference to FIGS.16A and 16B.

As shown in FIG. 16A, the larger the amount of exposure is, the largerthe inclination angle of a sidewall of a formed bank is. Morespecifically, when the exposure and development are performed with 200mJ of exposure amount, the inclination angle of a sidewall of the formedbank is 23°, whereas when the exposure and development are performedwith 300 mJ of exposure amount, the inclination angle of a sidewall ofthe formed bank is 38°. The results are also shown by the Atomic ForceMicroscope (AFM) in FIG. 16B.

Furthermore, as shown in FIGS. 16A and 16B, when the exposure anddevelopment in the first round is performed with 200 mJ of exposureamount and then the exposure and development in the second round isperformed with 100 mJ of exposure amount, the inclination angle of asidewall of the formed bank is 50°. This corresponds to themanufacturing method of Modification 2 and is considered to be effectivein creating a large inclination angle of the bank sidewall.

Note that in FIG. 16B, the horizontal axis represents the horizontaldirection, and the vertical axis represents the direction of height.

Embodiment 2

The following describes an overall structure of the display device inEmbodiment 2 with reference to FIGS. 17 and 18.

1. Structure of Display Panel 30

As shown in FIG. 17, in the display panel 30, as in the display panel 10in Embodiment 1, anodes 102 are formed above a TFT substrate(hereinafter simply referred to as a “substrate”) 101 in one-to-onecorrespondence with the sub-pixels 300 a, 300 b and 300 c, and on eachof the anodes 102, an electrode coating layer 103 is formed, and a holeinjection transporting layer 104 is layered on the electrode coatinglayers 103.

Above the hole injection transporting layer 104, banks 305 a, 305 b, 305c, and 305 d are formed from insulating material to define thesub-pixels 300 a, 300 b, and 300 c. An organic light-emitting layer isformed in each region of the sub-pixels 300 a, 300 b, and 300 c definedby the banks 305 a, 305 b, 305 c, 305 d, and an electron injectionlayer, a cathode, and a passivation layer are layered above the organiclight-emitting layer in this order (illustration of these is omitted inFIG. 17).

In the display panel 30 of the present embodiment, as is the case withthe display panel 10 in the above-described Embodiment 1, a pixel iscomposed of three sub-pixels 300 a, 300 b, and 300 c. In addition, inthe display panel 30 of the present embodiment, non-light-emitting cells300 d and 300 e are provided between the pixel and the adjacent pixelson both sides.

More specifically, as illustrated in FIG. 17, each of thenon-light-emitting cells 300 d and 300 e has an electrode (bus bar) 302,which is made of the same material as the anode 102, and an electrodecoating layer 303 covering the electrode 302. A hole injectiontransporting layer 104 is formed to cover each stack of the layersincluding the electrode coating layer 303. A cathode 108 (notillustrated) is formed on the hole injection transporting layer 104 suchthat the electrode 302 and the cathode 108 are electrically connected.Note that the organic light-emitting layer 106 is not formed in thenon-light-emitting cells 300 d and 300 e. The above structure makes itpossible to lower the electric resistance of the cathode 108 that iscomposed of ITO and the like, thereby preventing a voltage drop fromoccurring.

As illustrated in FIG. 17, in the display panel 30 of the presentembodiment, side walls 305 aa, 305 ba, 305 bb, 305 cb, 305 cc, and 305dc of the banks 305 a, 305 b, 305 c, and 305 d respectively form anglesθ3 aa, θ3 ba, θ3 bb, θ3 cb, θ3 cc, and θ3 dc with the surface of thehole injection transporting layer 104 as an underlying layer.

Here, in the present embodiment, the angles θ3 aa, θ3 ba, θ3 bb, θ3 cb,θ3 cc, and θ3 dc satisfy the relationships represented by the followingexpressions.

θ3cb>θ3aa=θ3ba=θ3bb=θ3cc  [Expression 7]

θ3dc>θ3aa=θ3ba=θ3bb=θ3 cc  [Expression 8]

Note that, in the present embodiment, the angles θ3 aa, θ3 ba, θ3 bb, θ3cb, θ3 cc, and θ3 dc are preferably set to the following ranges.

25°<θ3aa=θ3ba=θ3bb=θ3cc<35°  [Expression 9]

35°<θ3cb<45°  [Expression 10]

35°<θ3dc<45°  [Expression 11]

The reason why the inclination angles θ3 aa, θ3 ba, θ3 bb, θ3 cb, θ3 cc,and θ3 dc of the side walls 305 aa, 305 ba, 305 bb, 305 cb, 305 cc, and305 dc of the banks 305 a, 305 b, 305 c, and 305 d are defined by theabove-described Expressions 7 to 11 is that the non-light-emitting cells300 d and 300 e are provided between a pixel and the adjacent pixels onboth sides. Description of this is provided in connection withapplication of inks 3060 a, 3060 b, and 3060 c.

2. Manufacturing Method of Display Panel 30

The following describes the characteristic steps of the manufacturingmethod of the display panel 30 according to the present Embodiment withreference to FIGS. 18A to 18C. Note that the steps other than thoseillustrated in FIGS. 18A to 18C are the same as those of Embodiment 1.

As shown in FIG. 18A, ink 3060 a that includes an organic light-emittingmaterial is dripped into the opening (planned sub-pixel formation region3000 a) defined by the banks 305 a and 305 b by the inkjet method orother method. When the ink 3060 a is applied to the region between thebanks 305 a and 305 b, ink has not been applied to the left-hand side ofthe bank 305 a and the right-hand side of the bank 305 b, and thus thevapor concentration distribution is substantially uniform.

Following this, as shown in FIG. 18B, ink 3060 b that includes anorganic light-emitting material is dripped into the opening (plannedsub-pixel formation region 3000 b) defined by the banks 305 b and 305 cby the inkjet method or other method. Here, as described above,inclination angle θ3 cb of the sidewall 305 cb of the bank 305 c (seeFIG. 17) is set to satisfy the relationships represented by theabove-described Expression 7 (to be relatively larger than the otherinclination angles). As a result, the pinning location Q3 cb of the ink3060 b in the side wall 305 cb of the bank 305 c is higher in positionthan the pinning locations Q3 aa, Q3 ba, and Q3 bb.

Subsequently, as shown in FIG. 18C, ink 3060 c that includes an organiclight-emitting material is dripped into the opening (planned sub-pixelformation region 3000 c) defined by the banks 305 c and 305 d by theinkjet method or other method. Here, in the present embodiment, thenon-light-emitting cell 3000 d, to which ink is not applied, is presenton the right-hand side of the planned sub-pixel formation region 3000 c.Accordingly, the vapor concentration is lower in the right-hand side ofthe planned sub-pixel formation region 3000 c than in the left-handside. For this reason, as is the case with the inclination angle θ3 cbof the sidewall 305 cb of the bank 305 c, the inclination angle θ3 dc ofthe sidewall 305 dc of the bank 305 d on the planned sub-pixel formationregion 3000 c side (see FIG. 17) is set to satisfy the relationshipsrepresented by the above-described Expressions 7 and 8 (to be relativelylarger than the other inclination angles). As a result, the pinninglocation Q3 dc of the ink 3060 c in the side wall 305 dc of the bank 305d, as well as the pinning location Q3 cb of the ink 3060 b, is higher inposition than the other pinning locations.

Note that, although omitted from the drawings, subsequently, the displaypanel 30 is formed by layering, in order, the electron injection layer,cathode, passivation layer, etc.

With the above-described structure, even in the case where thenon-light-emitting cells 300 d and 300 e are provided between a pixeland the adjacent pixels on both sides, it is possible to prevent theorganic light-emitting layer from becoming uneven in film thickness inall sub-pixels 300 a, 300 b, and 300 c, and thus it is possible toprovide the display panel 30 having high light transmissivity.

Note that the structures other than those described in the presentembodiment are the same as those of Embodiment 1.

Embodiment 3

The following describes an overall structure of the display device inEmbodiment 3 with reference to FIGS. 19 and 20.

1. Structure of Display Panel 40

As shown in FIG. 19, in the display panel 40, as in the display panel 10in Embodiment 1, anodes 102 are formed above a TFT substrate(hereinafter simply referred to as a “substrate”) 101 in one-to-onecorrespondence with the sub-pixels 400 a, 400 b and 400 c, and on eachof the anodes 102, an electrode coating layer 103 is formed, and a holeinjection transporting layer 104 is layered on the electrode coatinglayers 103.

Above the hole injection transporting layer 104, banks 405 a, 405 b, 405c, and 405 d are formed from insulating material to define thesub-pixels 400 a, 400 b, and 400 c. An organic light-emitting layer isformed in each region of the sub-pixels 400 a, 400 b, and 400 c definedby the banks 405 a, 405 b, 405 c, 405 d, and an electron injectionlayer, a cathode, and a passivation layer are layered above the organiclight-emitting layer in this order (illustration of these is omitted inFIG. 19).

In the display panel 40 of the present embodiment, as is the case withthe display panel 30 in the above-described Embodiment 2, a pixel iscomposed of three sub-pixels 400 a, 400 b, and 400 c. In addition, inthe display panel 40 of the present embodiment, non-light-emitting cells400 d and 400 e are provided between the pixel and the adjacent pixelson both sides. With regard to the points described above, the displaypanel 40 is the same as the display panel 30 of Embodiment 2.

A illustrated in FIG. 19, as is the case with Embodiment 2, each of thenon-light-emitting cells 400 d and 400 e has an electrode (bus bar) 402,which is made of the same material as the anode 102, and an electrodecoating layer 403 covering the electrode 402. Furthermore, a holeinjection transporting layer 104 is formed to cover each stack of thelayers including the electrode coating layer 403. A cathode (notillustrated) is formed on the hole injection transporting layer 104 suchthat the electrode 402 and the cathode are electrically connected. Notethat the organic light-emitting layer is not formed in thenon-light-emitting cells 400 d and 400 e. As is the case with Embodiment2, this structure makes it possible to lower the electric resistance ofthe cathode that is composed of ITO and the like, thereby preventing avoltage drop from occurring.

As illustrated in FIG. 19, in the display panel 40 of the presentembodiment, side walls 405 aa, 405 ba, 405 bb, 405 cb, 405 cc, and 405dc of the banks 405 a, 405 b, 405 c, and 405 d respectively form anglesθ4 aa, θ4 ba, θ4 bb, θ4 cb, θcc, and θ4 dc with the surface of the holeinjection transporting layer 104, which is an underlying layer.

Here, in the present embodiment, the angles θ4 aa, θ4 ba, θ4 bb, θ4 cb,θcc, and θ4 dc satisfy the relationships represented by the followingexpressions.

θ4aa>θ4ba=θ4bb=θ4cb=θ4cc  [Expression 12]

θ4dc>θ4ba=θ4bb=θ4cb=θ4cc  [Expression 13]

Note that, in the present embodiment, the angles θ4 aa, θ4 ba, θ4 bb, θ4cb, θ4 cc, and θ4 dc are preferably set to the following ranges.

25°<θ4ba=θ4bb=θ4cb=θ4cc<35°  [Expression 14]

35°<θ4aa<45°  [Expression 15]

35°<θ4dc<45°  [Expression 16]

The reason why the inclination angles θ4 aa, θ4 ba, θ4 bb, θ4 cb, θ4 cc,and θ4 dc of the side walls 405 aa, 405 ba, 405 bb, 405 cb, 405 cc, and405 dc of the banks 405 a, 405 b, 405 c, and 405 d are defined by theabove Expressions 12 to 16 is that the non-light-emitting cells 400 dand 400 e are provided between a pixel and the adjacent pixels on bothsides, and in connection with this, an appropriate method for applyinginks 4060 a, 4060 b, and 4060 c is adopted as described below.

2. Manufacturing Method of Display Panel 40

The following describes the characteristic steps of the manufacturingmethod of the display panel 40 according to the present Embodiment withreference to FIG. 20. Note that the steps other than those illustratedin FIG. 20 are the same as those of Embodiment 1.

As shown in FIG. 20, the following inks are applied to the followingopenings at the same time by the inkjet method or the like: ink 4060 ato the planned sub-pixel formation region 4000 a; ink 4060 b to theplanned sub-pixel formation region 4000 b; and ink 4060 c to the plannedsub-pixel formation region 4000 c. At the time when the inks 4060 a,4060 b and 4060 c are applied, the vapor concentration distribution isuniform between the left-hand and right-hand sides in the X-axisdirection only in the planned sub-pixel formation region 4000 b which islocated at the central region of the pixel.

On the other hand, in the planned sub-pixel formation region 4000 a, thevapor concentration distribution is lower on the left-hand side than onthe right-hand side due to the presence of the non-light-emitting cell400 d on the left-hand side of the region 4000 a in the X-axisdirection. Similarly, in the planned sub-pixel formation region 4000 c,the vapor concentration distribution is lower on the right-hand sidethan on the left-hand side due to the presence of the non-light-emittingcell 400 e on the right-hand side of the region 4000 c in the X-axisdirection.

In the present embodiment, the non-light-emitting cells 400 d and 400 eare present on the left-hand and right-hand sides of the plannedsub-pixel formation regions 4000 a and 4000 c, respectively. In view ofthis, in the present embodiment, the inclination angles θ4 aa and θ4 dcof the respective side walls 405 aa and 405 dc of the banks 405 a and405 d are set to be larger than the other inclination angles θ4 ba, θ4bb, θ4 cb and θ4 cc. With this structure, the pinning locations Q4 aaand Q4 dc of the inks 4060 a and 4060 c in the respective sidewalls 405aa and 405 dc of the banks 105 a and 105 d become higher in positionthan the other pinning locations Q4 ba, Q4 bb, Q4 cb and Q4 cc.

Note that, although not illustrated, subsequently the ink is dried, andthe electron injection layer, cathode, passivation layer, etc, arelayered in this order to form the display panel 40.

With the above-described structure, even in the case where thenon-light-emitting cells 400 d and 400 e are each provided betweenadjacent pixels and the inks 4060 a, 4060 b and 4060 c are applied atthe same time, it is possible to restrict the film thickness of theorganic light-emitting layer from becoming uneven in each of thesub-pixels 400 a, 400 b and 400 c, and provide the display panel 40having excellent light-emitting characteristics.

Note that, with regard to the structural elements that are not describedin the present embodiment, corresponding structural elements ofEmbodiment 1 may be applied.

[Other Considerations]

Firstly, in the above Embodiments 1, 2 and 3 and Modifications 1 and 2,it is schematically illustrated that the surface of each sidewall of thebanks 105, 105 a-105 d, 105 x, 105 y, 305 a-305 e, and 405 a-405 e isplanar. However, the surface of each sidewall of the banks may notnecessarily be planar. For example,

FIG. 19A illustrates a bank 605 whose sidewall has two surfaces: asurface

extending from a point P₆₁ to a point P₆₂; and a surface extending fromthe point P₆₂ to a point P₆₃. In this case, a pinning location Qy1during ink application is present on the surface between the points P₆₂and P₆₃. Here, an inclination angle θy2 formed between this the surfaceand a virtual straight line L₁ passing through the point P₆, isimportant in the relationship with the pinning location.

However, the angle θy2 can be controlled by controlling an angle θy1,which is formed between the surface of the underlying layer, namely thehole injection transporting layer 104, and the surface between pointsP₆₁ and P₆, of the sidewall of the bank 605, when the bank 605 isformed. Thus, in the actuality, the above effects can be obtained bycontrolling the inclination angle θy1. For example, if a bank 705 isformed such that an angle θy11 formed between the surface of the holeinjection transporting layer 104 and a surface between points P₇₁ andP₇₂ is larger than the angle θy1 shown in FIG. 21A (see FIG. 21B), then,as shown in FIG. 21B, an angle θy12 formed between a surface betweenpoints P₇₂ and P₇₃ and a virtual straight line L₂ also becomes largerthan the angle θy2 shown in FIG. 21A.

Secondly, in the above Embodiments 1, 2 and 3 and Modifications 1 and 2,it is not specified to what part of the region of the display panel 10,30 or 40 the above-described structure can be applied. However, theabove-described structure may be applied to the entire region of thedisplay panel, or may be applied to a part of the region. As shown inFIG. 22, the display panel 10 can be divided formally into areas 10 aand 10 b in a direction along the surface of the display panel 10,wherein the area 10 a is located at the center, and the area 10 bsurrounds the area 10 a. The area 10 a is connected to a sourceelectrode or a drain electrode of the TFT layer below which the anodesare formed, and contributes to the emission of light. On the other hand,the area 10 b is not connected to any of the source electrode and drainelectrode of the TFT layer below which the anodes are formed, and doesnot contribute to the emission of light. It is considered that, if thearea 10 a is further divided formally into a central area 10 a 1 and asurrounding area 10 a 2, the uneven film thickness in the organiclight-emitting layers of the sub-pixels in the surrounding area 10 a 2would be more prominent due to the state of vapor concentrationdistribution during the application of ink.

Note that the combined area of the surrounding area 10 a 2 and the area10 b may occupy approximately 0.5% to several percent (for example, 1%)of the total area of the panel. This range is determined by takingaccount of the variation in film thickness of the organic light-emittinglayers when the inclination angles of the bank sidewalls are notadjusted.

In the above Embodiments 1, 2 and 3 and Modifications 1 and 2, thestructures are adopted by way of example to clearly explain thestructure, acts and effects of the present invention. Accordingly, thepresent invention is not limited to the above structures, except forsuch portions that are essential to the present invention. For example,the above Embodiment has adopted, as one example, a structure in whichthe anodes 102 are located below the organic light-emitting layers 106in the Z axis direction, as shown in FIG. 2. However, not limited tothis structure, the present invention may adopt a structure in which thecathodes 108 are located below the organic light-emitting layers 106 inthe Z axis direction.

The display panel has the top-emission structure when it adopts thestructure in which the cathodes 108 are located below the organiclight-emitting layers 106 in the Z axis direction. In that case, thecathodes 108 become the reflecting electrode layers, and the electrodecoating layers 103 are formed above the cathodes 108.

Furthermore, the above Embodiments 1, 2 and 3 and Modifications do notprovide a specific example of the appearance of the display device 1.However, the display device 1 may be formed as a part of a systemillustrated in FIG. 23, for example. Note that an organic EL displaydevice does not require a backlight as a liquid crystal display devicedoes, and thus is suitable for thin display devices and has excellentcharacteristics from the view point of system design.

Also, in the above Embodiments 1, 2 and 3 and Modifications 1 and 2, aso-called line bank structure is adopted for the banks 105, 105 a-105 f,105 x, 105 y, 305 a-305 e, 405 a-405 e, 605, and 705, as shown in FIG.3. However, not limited to this, the structure of pixel bank 805 shownin FIG. 24 may be adopted. In this structure, a display panel 80includes the pixel bank 805 which is composed of bank elements 805 a andbank elements 805 b, wherein the bank elements 805 a extend in the Yaxis direction and the bank elements 805 b extend in the X axisdirection.

As shown in FIG. 24, when the structure of pixel bank 805 is adopted,the same advantageous effects as the above ones can be obtained byincreasing the inclination angles of the sidewalls of the bank 805 inthe X and Y axis directions defining the sub-pixels 800 a, 800 b, and800 c. More specifically, the above advantageous effects can be obtainedby appropriately adjusting the inclination angles of the sidewallsindicated by the arrows B₁, B₂, B₃, and B₄.

Also, the inclination angles of the sidewalls of the banks adopted inthe above Embodiments 1, 2 and 3 and Modifications 1 and 2 may beindividually adjusted depending on the vapor concentration distributionobserved in the ink application process and drying process when theorganic light-emitting layers are formed in the manufacturing process.For example, if the drying device used in the ink drying process has astructure where the vapor flows from the outer circumference of thepanel toward the center of the panel, bank sidewalls where the organiclight-emitting layers are large in film thickness may have increasedinclination angles. This enables the film thickness of the organiclight-emitting layers to be uniform, thereby reducing the unevenness inluminance over the entire panel.

In the above Embodiments 1, 2 and 3 and in Modifications 1 and 2, theinclination angle (taper angle) of bank sidewalls is set in the samemanner, without distinction between the luminescent colors (red, green,and blue). However, there may be a case where the organic light-emittingmaterials of the ink for the respective luminescent colors havedifferent characteristics. In that case, the inclination angles of thebank sidewalls may be defined in accordance with the ink characteristicsof each luminescent color.

INDUSTRIAL APPLICABILITY

The present invention is useful for providing an organic light-emittingpanel and an organic display device that exhibit substantially evenluminance and are capable of displaying high-quality images.

REFERENCE SIGNS LIST

-   -   1 display device    -   10, 30, 40, 80 display panel    -   10 a 1 light-emitting central area    -   10 a 2 light-emitting surrounding area    -   10 b dummy area    -   20 drive control unit    -   21-24 drive circuit    -   25 control circuit    -   100, 100 a-100 c, 300 a-300 c, 400 a-400 c sub-pixel    -   101 substrate    -   102 anode    -   103 electrode coating layer    -   104 hole injection layer    -   105, 105 a-105 d, 105 x, 105 y, 305 a-305 e, 405 a-405 e, 605,        705, 805 bank 106, 106 a, 106 c, 106 x, 106 y organic        light-emitting layer    -   107 electron injection layer    -   108 cathode    -   109 passivation layer    -   300 d, 300 e, 400 d, 400 e non-light-emitting cell 501-505 mask    -   1000 a-1000 c, 3000 a-3000 c, 4000 a-4000 c region in which        sub-pixel is to be formed 1050, 1051 a, 1051 b, 1051 e, 1051 f        bank material layer 1060 a-1060 c, 106θx, 1060 y, 3060 a-3060 c,        4060 a-4060 c ink 3000 d, 3000 e, 4000 d, 4000 e region in which        non-light-emitting cell is to be formed

1. An organic light-emitting panel comprising: an array of a pluralityof pixels; a plurality of light-emitting cells which, provided in eachpixel and arranged in an alignment, emit light of different colors, eachlight-emitting cell including an underlying layer, a first electrodeprovided in the underlying layer, an organic light-emitting layer, and asecond electrode formed on an opposite side of the organiclight-emitting layer from the underlying layer; and a plurality of bankswhich, formed above the underlying layer, define each light-emittingcell by separating the light-emitting cells one from another, theplurality of pixels including a pixel that is structured such that twoinner sidewalls, which face each other in two adjacent banks defining apredetermined light-emitting cell among the plurality of light-emittingcells, have different inclination angles that are both acute angles. 2.The organic light-emitting panel of claim 1, wherein in each of one ormore light-emitting cells other than the predetermined light-emittingcell in the pixel that is structured such that the two inner sidewallsfacing each other in the two adjacent banks defining the predeterminedlight-emitting cell have different inclination angles that are bothacute angles, two inner sidewalls facing each other have equalinclination angles that are both acute angles.
 3. The organiclight-emitting panel of claim 1, wherein the plurality of light-emittingcells in each pixel include at least a first light-emitting cell locatedat an end of the alignment, a second light-emitting cell located at acentral portion of the alignment, and a third light-emitting celllocated at another end of the alignment, the plurality of pixels arearranged to be continuously adjacent to each other, and the plurality ofpixels include a pixel that is structured such that two inner sidewalls,which face each other in two adjacent banks defining the firstlight-emitting cell, have equal inclination angles that are both acuteangles, two inner sidewalls, which face each other in two adjacent banksdefining the second light-emitting cell, have different inclinationangles that are both acute angles, and two inner sidewalls, which faceeach other in two adjacent banks defining the third light-emitting cell,have equal inclination angles that are both acute angles.
 4. The organiclight-emitting panel of claim 1, wherein the plurality of light-emittingcells in each pixel include at least a first light-emitting cell locatedat an end of the alignment, a second light-emitting cell located at acentral portion of the alignment, and a third light-emitting celllocated at another end of the alignment, a non-light-emitting cell isprovided between each pair of adjacent pixels, a bank is providedbetween each pair of a pixel and a non-light-emitting cell that areadjacent to each other, the bank separating the pixel from thenon-light-emitting cell, and the plurality of pixels include a pixelthat is structured such that two inner sidewalls, which face each otherin two adjacent banks defining the first light-emitting cell, have equalinclination angles that are both acute angles, two inner sidewalls,which face each other in two adjacent banks defining the secondlight-emitting cell, have different inclination angles that are bothacute angles, and two inner sidewalls, which face each other in twoadjacent banks defining the third light-emitting cell, have differentinclination angles that are both acute angles.
 5. The organiclight-emitting panel of claim 1, wherein the plurality of light-emittingcells in each pixel include at least a first light-emitting cell locatedat an end of the alignment, a second light-emitting cell located at acentral portion of the alignment, and a third light-emitting celllocated at another end of the alignment, a non-light-emitting cell isprovided between each pair of adjacent pixels, a bank is providedbetween each pair of a pixel and a non-light-emitting cell that areadjacent to each other, the bank separating the pixel from thenon-light-emitting cell, and the plurality of pixels include a pixelthat is structured such that two inner sidewalls, which face each otherin two adjacent banks defining the first light-emitting cell, havedifferent inclination angles that are both acute angles, two innersidewalls, which face each other in two adjacent banks defining thesecond light-emitting cell, have equal inclination angles that are bothacute angles, and two inner sidewalls, which face each other in twoadjacent banks defining the third light-emitting cell, have differentinclination angles that are both acute angles.
 6. The organiclight-emitting panel of claim 4, wherein each non-light-emitting cellincludes none of the organic light-emitting layers and includes thesecond electrode and a third electrode that is made of a same materialas the first electrodes, the third electrode and the second electrodebeing electrically connected with each other.
 7. The organiclight-emitting panel of claim 1, wherein two regions adjacent to thepredetermined light-emitting cell have different ink vaporconcentrations when ink is applied to the predetermined light-emittingcell, and among two inner sidewalls facing each other in two adjacentbanks defining the predetermined light-emitting cell, a sidewall of abank, which is located on a side of a region having a lower ink vaporconcentration among the two regions, has an inclination angle that is anacute angle and larger than an inclination angle of a sidewall of abank, which is located on a side of a region having a higher ink vaporconcentration among the two regions.
 8. The organic light-emitting panelof claim 1, wherein a type of ink corresponding to the predeterminedlight-emitting cell is applied to the predetermined light-emitting cellin a state where a type of ink corresponding to one light-emitting cellamong two light-emitting cells that are, in a same pixel, adjacent tothe predetermined light-emitting cell, has been applied to the onelight-emitting cell and before another type of ink corresponding to theother light-emitting cell among the two light-emitting cells starts tobe applied to the other light-emitting cell, and a sidewall of a banklocated on a side of the other light-emitting cell has an inclinationangle that is an acute angle and larger than an inclination angle of asidewall of a bank located on a side of the one light-emitting cell. 9.The organic light-emitting panel of claim 1, wherein two regionsadjacent to the predetermined light-emitting cell have different inkvapor concentrations when ink is applied to the predeterminedlight-emitting cell, and two regions adjacent to a light-emitting cell,which is different from the predetermined light-emitting cell, haveequal ink vapor concentrations when ink is applied to the light-emittingcell.
 10. The organic light-emitting panel of claim 1, wherein theplurality of light-emitting cells provided in each pixel include atleast a first light-emitting cell located at an end of the alignment, asecond light-emitting cell located at a central portion of thealignment, and a third light-emitting cell located at another end of thealignment, each organic light-emitting layer being formed by applying,for each pixel, at least three types of ink, which correspond one-to-oneto the different colors of light, respectively to the at least threelight-emitting cells in an order of the first light-emitting cell, thesecond light-emitting cell and the third light-emitting cell, theplurality of pixels are arranged to be continuously adjacent to eachother, and in each pixel, two inner sidewalls, which face each other intwo adjacent banks defining the first light-emitting cell, have equalinclination angles that are both acute angles, two inner sidewalls,which face each other in two adjacent banks defining the secondlight-emitting cell, have different inclination angles that are bothacute angles, and two inner sidewalls, which face each other in twoadjacent banks defining the third light-emitting cell, have equalinclination angles that are both acute angles.
 11. The organiclight-emitting panel of claim 10, wherein among two inner sidewallsfacing each other in two adjacent banks defining the secondlight-emitting cell, a sidewall of a bank located on a side of the thirdlight-emitting cell has an inclination angle that is an acute angle andlarger than an inclination angle of a sidewall of a bank located on aside of the first light-emitting cell.
 12. The organic light-emittingpanel of claim 11, wherein the sidewall of the bank located on the sideof the first light-emitting cell among the two inner sidewalls facingeach other in the two adjacent banks defining the second light-emittingcell, and the two inner sidewalls facing each other in the two adjacentbanks defining the first light-emitting cell, have equal inclinationangles that are acute angles.
 13. The organic light-emitting panel ofclaim 12, wherein the sidewall of the bank located on the side of thefirst light-emitting cell among the two inner sidewalls facing eachother in the two adjacent banks defining the second light-emitting cell,and the two inner sidewalls facing each other in the two adjacent banksdefining the third light-emitting cell, have equal inclination anglesthat are acute angles.
 14. The organic light-emitting panel of claim 13,wherein among the two inner sidewalls facing each other in the twoadjacent banks defining the second light-emitting cell, the sidewall ofthe bank located on the side of the third light-emitting cell has aninclination angle of at least 35 degrees and at most 45 degrees, amongthe two inner sidewalls facing each other in the two adjacent banksdefining the second light-emitting cell, the sidewall of the banklocated on the side of the first light-emitting cell has an inclinationangle of at least 25 degrees and at most 35 degrees, each of the twoinner sidewalls facing each other in the two adjacent banks defining thefirst light-emitting cell has an inclination angle of at least 25degrees and at most 35 degrees, and each of the two inner sidewallsfacing each other in the two adjacent banks defining the thirdlight-emitting cell has an inclination angle of at least 25 degrees andat most 35 degrees.
 15. The organic light-emitting panel of claim 1,wherein the plurality of light-emitting cells provided in each pixelinclude at least a first light-emitting cell located at an end of thealignment, a second light-emitting cell located at a central portion ofthe alignment, and a third light-emitting cell located at another end ofthe alignment, each organic light-emitting layer being formed byapplying, for each pixel, at least three types of ink, which correspondone-to-one to the different colors of light, respectively to the atleast three light-emitting cells in an order of the first light-emittingcell, the second light-emitting cell and the third light-emitting cell,a non-light-emitting cell is provided between each pair of adjacentpixels, a bank is provided between each pair of a pixel and anon-light-emitting cell that are adjacent to each other, the bankseparating the pixel from the non-light-emitting cell, and in eachpixel, two inner sidewalls, which face each other in two adjacent banksdefining the first light-emitting cell, have equal inclination anglesthat are both acute angles, two inner sidewalls, which face each otherin two adjacent banks defining the second light-emitting cell, havedifferent inclination angles that are both acute angles, and two innersidewalls, which face each other in two adjacent banks defining thethird light-emitting cell, have different inclination angles that areboth acute angles.
 16. The organic light-emitting panel of claim 15,wherein among the two inner sidewalls facing each other in the twoadjacent banks defining the second light-emitting cell. the sidewall ofthe bank located on the side of the third light-emitting cell has aninclination angle that is an acute angle and larger than an inclinationangle of the sidewall of the bank located on the side of the firstlight-emitting cell, and among the two inner sidewalls facing each otherin the two adjacent banks defining the third light-emitting cell, thesidewall of the bank located on the side of the non-light-emitting cellhas an inclination angle that is an acute angle and larger than aninclination angle of the sidewall of the bank located on the side of thesecond light-emitting cell.
 17. The organic light-emitting panel ofclaim 16, wherein the sidewall of the bank located on the side of thethird light-emitting cell among the two inner sidewalls facing eachother in the two adjacent banks defining the second light-emitting cell,and the sidewall of the bank located on the side of thenon-light-emitting cell among the inner sidewalls facing each other inthe two adjacent banks defining the third light-emitting cell, haveequal inclination angles that are both acute angles.
 18. The organiclight-emitting panel of claim 15, wherein the sidewall of the banklocated on the side of the first light-emitting cell among the two innersidewalls facing each other in the two adjacent banks defining thesecond light-emitting cell, and the two inner sidewalls facing eachother in the two adjacent banks defining the first light-emitting cell,have equal inclination angles that are acute angles.
 19. The organiclight-emitting panel of claim 18, wherein the sidewall of the banklocated on the side of the second light-emitting cell among the twoinner sidewalls facing each other in the two adjacent banks defining thethird light-emitting cell, and the two inner sidewalls facing each otherin the two adjacent banks defining the first light-emitting cell, haveequal inclination angles that are acute angles.
 20. The organiclight-emitting panel of claim 18, wherein among the two inner sidewallsfacing each other in the two adjacent banks defining the secondlight-emitting cell, the sidewall of the bank located on the side of thethird light-emitting cell has an inclination angle of at least 35degrees and at most 45 degrees, among the two inner sidewalls facingeach other in the two adjacent banks defining the third light-emittingcell, the sidewall of the bank located on the side of thenon-light-emitting cell has an inclination angle of at least 35 degreesand at most 45 degrees, among the two inner sidewalls facing each otherin the two adjacent banks defining the second light-emitting cell, thesidewall of the bank located on the side of the first light-emittingcell has an inclination angle of at least 25 degrees and at most 35degrees, among the two inner sidewalls facing each other in the twoadjacent banks defining the third light-emitting cell, the sidewall ofthe bank located on the side of the second light-emitting cell has aninclination angle of at least 25 degrees and at most 35 degrees, andeach of the two inner sidewalls facing each other in the two adjacentbanks defining the first light-emitting cell has an inclination angle ofat least 25 degrees and at most 35 degrees.
 21. The organiclight-emitting panel of claim 1, wherein the plurality of light-emittingcells provided in each pixel include at least a first light-emittingcell located at an end of the alignment, a second light-emitting celllocated at a central portion of the alignment, and a thirdlight-emitting cell located at another end of the alignment, eachorganic light-emitting layer being formed by applying, for each pixel,at least three types of ink, which correspond one-to-one to thedifferent colors of light, respectively to the at least threelight-emitting cells at the same time, a non-light-emitting cell isprovided between each pair of adjacent pixels, a bank is providedbetween each pair of a pixel and a non-light-emitting cell that areadjacent to each other, the bank separating the pixel from thenon-light-emitting cell, and in each pixel, two inner sidewalls, whichface each other in two adjacent banks defining the first light-emittingcell, have different inclination angles that are both acute angles, twoinner sidewalls, which face each other in two adjacent banks definingthe second light-emitting cell, have equal inclination angles that areboth acute angles, and two inner sidewalls, which face each other in twoadjacent banks defining the third light-emitting cell, have differentinclination angles that are both acute angles.
 22. The organiclight-emitting panel of claim 21, wherein among the two inner sidewallsfacing each other in the two adjacent banks defining the firstlight-emitting cell, the sidewall of the bank located on the side of thenon-light-emitting cell has an inclination angle that is an acute angleand larger than an inclination angle of the sidewall of the bank locatedon the side of the second light-emitting cell, and among the two innersidewalls facing each other in the two adjacent banks defining the thirdlight-emitting cell, the sidewall of the bank located on the side of thenon-light-emitting cell has an inclination angle that is an acute angleand larger than an inclination angle of the sidewall of the bank locatedon the side of the second light-emitting cell.
 23. The organiclight-emitting panel of claim 22, wherein the sidewall of the banklocated on the side of the non-light-emitting cell among the two innersidewalls facing each other in the two adjacent banks defining the firstlight-emitting cell, and the sidewall of the bank located on the side ofthe non-light-emitting cell among the inner sidewalls facing each otherin the two adjacent banks defining the third light-emitting cell, haveequal inclination angles that are both acute angles.
 24. The organiclight-emitting panel of claim 21, wherein the sidewall of the banklocated on the side of the second light-emitting cell among the twoinner sidewalls facing each other in the two adjacent banks defining thefirst light-emitting cell, and the two inner sidewalls facing each otherin the two adjacent banks defining the second light-emitting cell, haveequal inclination angles that are acute angles.
 25. The organiclight-emitting panel of claim 24, wherein the sidewall of the banklocated on the side of the second light-emitting cell among the twoinner sidewalls facing each other in the two adjacent banks defining thethird light-emitting cell, and the two inner sidewalls facing each otherin the two adjacent banks defining the second light-emitting cell, haveequal inclination angles that are acute angles.
 26. The organiclight-emitting panel of claim 25, wherein among the two inner sidewallsfacing each other in the two adjacent banks defining the firstlight-emitting cell, the sidewall of the bank located on the side of thenon-light-emitting cell has an inclination angle of at least 35 degreesand at most 45 degrees, among the two inner sidewalls facing each otherin the two adjacent banks defining the third light-emitting cell, thesidewall of the bank located on the side of the non-light-emitting cellhas an inclination angle of at least 35 degrees and at most 45 degrees,among the two inner sidewalls facing each other in the two adjacentbanks defining the first light-emitting cell, the sidewall of the banklocated on the side of the second light-emitting cell has an inclinationangle of at least 25 degrees and at most 35 degrees, among the two innersidewalls facing each other in the two adjacent banks defining the thirdlight-emitting cell, the sidewall of the bank located on the side of thesecond light-emitting cell has an inclination angle of at least 25degrees and at most 35 degrees, and each of the two inner sidewallsfacing each other in the two adjacent banks defining the secondlight-emitting cell has an inclination angle of at least 25 degrees andat most 35 degrees.
 27. The organic light-emitting panel of claim 1,wherein each inclination angle is an angle formed by a side wall of abank and an upper surface of the underlying layer on which the bank isprovided.
 28. The organic light-emitting panel of claim 1, wherein theunderlying layer includes a TFT layer formed below the first layer, andin the pixel that is structured such that the two inner sidewalls facingeach other in the two adjacent banks defining the predeterminedlight-emitting cell have different inclination angles, the firstelectrode and the TFT layer are electrically connected with each other.29. An organic display device including the organic light-emitting paneldefined in claim
 1. 30. A manufacturing method of an organiclight-emitting panel including an array of a plurality of pixels, themanufacturing method comprising: a first step of forming, on asubstrate, an underlying layer including a plurality of firstelectrodes; a second step of layering a photoresist material on theunderlying layer; a third step of forming, for each pixel, a pluralityof openings corresponding to a plurality of light-emitting cells byperforming an exposure with a mask laid on the layered photoresistmaterial to form a pattern, and foaming a plurality of banks to defineeach light-emitting cell by separating the light-emitting cells one fromanother; a fourth step of forming a plurality of organic light-emittinglayers by dripping ink that includes organic light-emitting materialsinto the plurality of openings corresponding to the plurality oflight-emitting cells, and drying the ink; and a fifth step of forming asecond electrode above each organic light-emitting layer, wherein in thethird step, at least one pixel among the plurality of pixels is formedsuch that two inner sidewalls, which face each other in two adjacentbanks defining a predetermined light-emitting cell among the pluralityof light-emitting cells, have different inclination angles that are bothacute angles.
 31. The manufacturing method of claim 30, wherein in thethird step, the at least one pixel is formed such that two innersidewalls, which face each other in two adjacent banks defining alight-emitting cell other than the predetermined light-emitting cell,have equal inclination angles that are both acute angles.
 32. Themanufacturing method of claim 30, wherein in the third step, when theexposure of the photoresist material is performed, the two innersidewalls facing each other in the two adjacent banks defining thepredetermined light-emitting cell are formed to have differentinclination angles, by causing portions of the photoresist materialcorresponding to the sidewalls of the banks defining the predeterminedlight-emitting cell to be exposed to different amounts of light.
 33. Themanufacturing method of claim 30, wherein in the third step, when theexposure of the photoresist material is performed, the two innersidewalls facing each other in the two adjacent banks defining thepredetermined light-emitting cell are formed to have differentinclination angles, by using masks that are different in lighttransmissivity at portions of the photoresist material corresponding tothe sidewalls of the banks defining the predetermined light-emittingcell.
 34. The manufacturing method of claim 30, wherein in the thirdstep, after the photoresist material is exposed and developed, the twoinner sidewalls facing each other in the two adjacent banks defining thepredetermined light-emitting cell are formed to have differentinclination angles, by additionally performing an exposure process ontoa portion of the photoresist material corresponding to one of the twoinner sidewalls facing each other in the two adjacent banks defining thepredetermined light-emitting cell.
 35. An organic display deviceincluding the organic light-emitting panel manufactured by themanufacturing method defined in claim 30.